Throwing by the Numbers: Data-based pitching success stories

By Nic Osanic

As we’ve seen, there are many kinds of adjustments that pitchers can make to improve their performance.

Some pitchers may change their arm slot, find new grips, or alter other elements of their delivery. In the end, there is a good chance that every pitcher can find subtle ways to improve no matter how good they already are. In this article, we are going to explore many examples of pitchers decreasing the usage of their sinker and 2-Seamer in-favour of other pitches. It is worth noting, however, that this strategy may not be necessary for everyone. Some pitchers such as Jordan Hicks (100.6 mph average sinker velocity) can use the pitch effectively and therefore don’t need to remove it from their repertoire (although Hicks’ career K/9 of 8.55 is surprisingly low for someone who averages over 100 mph).


First, here is a refresher of our major pitch type effectiveness chart from earlier in the series:

Interestingly, the splitter appears to be the best pitch in baseball, despite being thrown at an abysmal rate of 1.52%. It generates the most swinging strikes and has the second-best results when contacted against. Although the low usage rate could signify that pitchers only throw splitters if they have an elite offering, keep in mind that there have been over two-million total pitches thrown over the last three seasons, so 1.52% of two-million represents a large number of splitters thrown (approximately 33,000).

Pre-2020 breakouts

In this section, we will not include 2020 stats, as I find it unfair to use a pitcher’s stats based on two months coming off an interrupted “Spring” Training. There had been talk earlier in the season that many players were expecting more preparation time. Since pitchers are creatures of habit, we can link the abnormal offseason to some of the major pitcher injuries we saw immediately after the season started. The likes of Kirby Yates (4.1 innings pitched before being shut down for the year), Justin Verlander (underwent Tommy John Surgery after injuring his throwing arm in his first start of the season), Mike Soroka (pitched 13.1 innings before his Achilles blew out), and Corey Kluber (suffered a shoulder tear to his throwing arm after just one inning) all went down shortly after the season began. We can add many more names to this list (such as Clayton Kershaw who missed a few starts to open the year), but these were the most serious injuries. Additionally, keep in mind that we mentioned Gerrit Cole and Lucas Giolito in previous articles.


Photo credited to Getty Images

Kirby Yates

The career of Kirby Yates is a feel-good story.

Originally a 26th round selection out of high school in 2005 by the Boston Red Sox, Yates decided to go to college instead. He never got drafted again and instead, signed as a minor league free agent with the Tampa Bay Rays. After working his way through the minors, he made his debut with the Rays as a 27-year-old rookie in 2014. Unfortunately for Yates, his “stuff” was not really impactful at the highest level, so the Rays traded him to the Cleveland Indians for cash considerations at the end of 2015.

In that same offseason, he was traded once again for cash to the New York Yankees, and at the end of the 2016 season, the Los Angeles Angels claimed Yates off of waivers. Yates started the 2017 season with the Angels but only made a total of one appearance with them. As it turned out, it was an important one. Yates faced five batters and gave up two home runs. After watching this game and his previous career struggles, the Angels decided that they had seen enough of Yates and put him on waivers after one game.

Seemingly unknown to the Angels, Yates discovered a new weapon in that contest. He threw a total of two splitters for the first time in his career that game and generated a swinging strike off one of them. A few days later, the San Diego Padres scooped him up without any return going to Los Angeles, and the rest is history.


Yates’ splitter has become one of the best pitches in the game. He increased his usage from 10.9% in 2017 to 42.1% in 2019, accompanied by a drop in ERA from 3.79 to 1.19 over the same timeframe. His splitter success has come at the expense of his slider – which produced below-average results from 2014-17 but has started to become better recently. This could be the result of a change in horizontal release point which would potentially allow his slider to break across more of the plate – creating more swings and misses. Kirby Yates dominated in 2019, and his peripherals show that he is the real deal. The thought of there potentially being minor tweaks that could make him even better (he has below-average vertical fastball movement and his active spin rate of 93.1% ranked 50th) is scary.


Photo credited to Getty Images

Charlie Morton

Charlie Morton is another pitcher who benefited from leaving Pittsburgh and their “pitch to contact” methodology. In Pittsburgh, Morton threw his sinker 48% of the time. This pitch produced average numbers when contacted against but had trouble generating whiffs. Morton’s high usage of this ineffective pitch is likely the reason why his K/9 was only 6.33 during his tenure with the Pirates. On the other hand, Morton’s curveball was his best pitch, yet only used it 20.9% of the time. At the end of 2015, Morton was traded to Philadelphia but only pitched in four games for them during the 2016 season due to a season-ending hamstring surgery.

Confident they could squeeze hidden value out of him the Houston Astros signed Morton to a two-year contract in November 2016. With Houston, Morton decreased his sinker usage by 13.3% and upped his curveball by 7.9%. His 4-Seam fastball also got significantly better as his swinging strike rate went from 9% to 14.6% when thrown high. This likely resulted from an increased velocity, which rose by 2.9 mph (likely due to an increase in spin rate). Morton’s velocity even touched 98.5 mph as he closed out the final game of the 2017 World Series. Morton was quite good in Houston but, he still found another gear last season.


In Tampa Bay, Morton became an elite starting pitcher. 

Once again, he substituted his worst pitch for his best pitch. His curveball usage jumped to 37.8% and his sinker dropped to 19.1%. A noteworthy aside is his usage of the high 4-Seam fastball. In Houston, he threw the pitch 9.8% of the time, and the results were poor when contact was made. However, Morton doubled down on the pitch and upped his usage to 18%. Although his .376 xwOBA when contacted still was not great, the pitch did show improvement. His swinging strike rate of 17.8% on high 4-Seam fastballs was enough for 6th place among qualified starting pitchers. By properly utilizing his best pitches, Charlie Morton finished 3rd in Cy Young voting in 2019 and transformed himself into one of baseball’s best starting pitchers.


Photo credited to Kim Klement — USA Today

Tyler Glasnow

Tyler Glasnow is a rare breed.

He is a starting pitcher who survives by primarily throwing two pitches; a dominant curveball and a 4-Seam fastball that can touch 100 mph. Glasnow was always a top prospect in the Pirates system but never had success when called up to the big league team. Part of the blame is on his sinker. Glasnow threw the pitch 11.5% of the time, but it had very little bat-missing ability and got crushed when contacted against. After a couple of seasons of disappointment, the Pirates traded Glasnow to Tampa Bay in the soon-to-be infamous Chris Archer trade.


With the Rays, Glasnow completely dropped his sinker and threw both more curveballs and high fastballs. The results, although in only twelve starts, were incredible. Glasnow’s ERA of 1.78 was 1st among starters with a minimum of 60 innings pitched. Although he will likely regress to some extent (a 1.78 ERA is difficult to repeat for a starting pitcher, especially over the course of a full season), Glasnow is only 26 years old and has the potential to be even better. In 2018, Glasnow threw a slider 10.2% of the time. This pitch generated a .292 xwOBA and amazingly, 27.4% of all the sliders he threw resulted in a swing and a miss. If Glasnow feels that his 2-pitch approach is too predictable, bringing back his slider could make him one of baseball’s next aces.


Photo credited to Getty Images

Pat Corbin

Patrick Corbin is another example of a guy getting average results by relying on his sinker despite owning an elite secondary pitch. Once again, some tinkering to his arsenal unlocked hidden potential. Corbin decided to turn his slider into his top offering and decreased the usage of his sinker. He also developed a curveball in 2018, which has generated plenty of swings-and-misses but generates significant contact.


Such change increased his strikeout numbers and turned Corbin into a top starter in the MLB. However, Corbin appears to have even more potential. If he manages to substitute some of his sinkers for high 4-Seam fastballs, he could become even better, shown by his 10.6% swinging strike rate on the high 4-Seamer compared to 5% on his sinker. Although both pitches get hit hard, his high 4-Seam fastball has also induced slightly weaker contact.

Since he threw fastballs and sinkers a combined 53.7% of the time, doubling his swinging strike rate and reducing the quality of contact against him by switching from sinkers to high fastballs could pay huge dividends in the future. If he were to make this change, Patrick Corbin could cement himself into Scherzer and deGrom territory in the National League.


Photo credited to Kevin Jairaj — USA Today

Lance Lynn

Using Lance Lynn as an example sort of feels like cheating since his run prevention stats barely changed. His 3.57 ERA from 2011 to 2018 was actually better than his 3.67 ERA from the 2019 season, yet Lynn put up a 6.8 fWAR in 2019. So what turned Lynn into baseball’s 3rd most valuable starting pitcher despite posting an ERA below his career average? Part of the answer revolves around his increase in cutter usage and decrease in sinker usage. 

In 2019, Lynn threw his cutter 12.3% more and threw his sinker 12.1% less. His cutter both performed better against contact and missed more bats compared to his sinker, which helped improve his K/9 from 8.57 to 10.63 and increased his WAR, as more strikeouts equalled less dependence on defence. Part of the answer also likely comes from his increase in swinging strike rate on each of his pitches. This result is likely due to an increase in his spin rate on each of these pitches which led to slightly more velocity and movement.

To improve, even more, Lynn should further reduce his sinker usage and throw more curveballs as this pitch only yielded a .320 xwOBA and generated a 15.3% swinging strike rate in 2019. Despite being debatably his best pitch, Lynn only threw his curveball 9.2% of the time last season and just 9.4% during his entire career.


It should be worth noting that Lynn has followed up his dominant 2019 campaign with an even better 2020. In thirteen starts this year, Lynn put up a 3.32 ERA and was one of the top trade candidates at this year’s deadline. To make himself even better, Lynn reduced his number of fastballs thrown at the bottom and middle parts of the strike zone from 28.8% in 2019 to 23.4% in 2020. To make up for this reduction, he upped his cutter usage by 6.4%. With his contract set to expire after 2021, expect the uncompetitive Texas Rangers to explore his trade market once again in the offseason.

Legitimate 2020 breakouts

This section will only contain pitchers whom I can prove had legitimate breakthroughs in the shortened 2020 season. A legitimate breakthrough qualifies as a pitcher whose numbers during the season were seemingly sustainable and would not regress a whole lot over the course of a 162 game season. I will not include pitchers such as Corbin Burnes who had great peripheral stats (results that pitchers have control over and exclude defence such as strikeouts, walks, and soft contact) during 2019 but did not see the ERA results. Such a situation would be too easy and not necessarily constitute a \”breakout,\” as their peripheral numbers were already good. Now that we have defined the classification of a breakout in 2020, here are a few notable examples.


Photo retrieved from ESPN

Dylan Bundy

At the end of 2019, after nine disappointing and injury-ridden years in the Baltimore Orioles organization (he sported a 4.67 career ERA), Dylan Bundy was one of the few remaining pieces of the Orioles’ mid-2010’s competitive window still under contract. The Orioles, now led by a new front office after a disastrous 2018 season, had decided that a painful rebuild would be best for the long-term success of the franchise, which meant stockpiling their prospect pool at the expense of anyone on their roster with trade value. 

Bundy – the former 4th overall pick in 2011, who once featured a 100 mph fastball in college – had seen his average fastball velocity drop to a mere 91.1 mph during the 2019 campaign due to an accumulation of arm injuries. Nevertheless, Bundy was still just 27 years old and the Los Angeles Angels – desperate for starting pitching after missing out on the big names of the free-agent market – acquired him for a package of low-mid tier prospects in the 2019 offseason. Fast-forward one year, and Dylan Bundy had become one of the most surprising breakthrough stories of the 2020 season.


So how did he do it? 

Well, Bundy didn’t exactly reinvent himself with the Angels, as his average fastball velocity once again dropped to the lowest it had ever been at 90 mph, and his K/9 rate of 9.87 was nothing special from a league perspective but still a career-high. His command had never been a problem, but it helped that his 2.33 BB/9 set a new career low. However, Bundy’s most significant improvement was his sudden ability to suppress home runs. 

Entering the 2020 season, Bundy was averaging 1.67 home runs allowed per nine innings for his career. Among qualified pitchers from 2012 to 2019, Bundy ranked 367th out of 369 pitchers in HR/9 allowed – only finishing lower than A.J. Griffin and Josh Tomlin. Home runs had been the plague of Bundy’s career thus far, but with his fastball velocity continuing to plummet, a fix was not looking promising.


Needing an alternative to his ailing fastball as a pairing for his wipeout slider, Bundy went to work on his changeup. It started during the 2019 season when Bundy saw a dramatic spike in the downward movement of this pitch (green line). What used to be his most home run-prone pitch (21 homers allowed on 1059 changeups from 2012-18) now became a weapon (6 homers allowed on 700 changeups from 2019-20).

Unfortunately, Bundy’s fastball was still utilized far too often in 2019 for him to have success. So when 2020 rolled around, Bundy lowered his fastball usage, especially where it got hit hardest, and increased the usage of his changeup. With his changeup fixed and fastball usage lowered, Bundy finished 8th among qualified pitchers with a 0.69 HR/9. Whether that number is sustainable over a 162-game season remains to be seen as Charlie Morton’s 0.69 HR/9 in 2019 led the entire MLB. However, Dylan Bundys’ season should have been even better.


For whatever reason, Bundy spent his last two starts deviating from what had previously been working for him. He dropped his slider usage by 10.2% and went back to his pre-2020 fastball usage. With his diminished velocity, this was not the best idea, and his numbers struggled mightily. I do acknowledge that this sample size was only two games and his quality of contact allowed suggests that he shouldn’t have been as bad as his 9.39 ERA indicates.

However, we can attribute his lack of strikeouts and increased walk rate to the fact that batters don’t swing as often when you miss the strike zone with fastballs (especially with low ones) compared to breaking balls and offspeed pitches. Hopefully entering next season, Bundy realizes where his success came from and doesn’t fall back in love with his pre-2020 pitching tendencies.


Photo credited to Getty Images

Tyler Mahle

Tyler Mahle is a pitcher who completely reimagined himself in 2020. After three years of mediocrity from 2017 to 2019 (combined 4.88 ERA), Mahle quietly emerged as a quality starting pitcher in the 2020 Cincinnati Reds’ rotation. Overshadowed by the likes of Trevor BauerSonny Gray, and Luis Castillo, Mahle posted a career-low 3.59 ERA. Something new to Mahle’s professional career in 2020 was his sudden ability to record strikeouts. 

Coming into the season, his highest qualified K/9 rate in both the MLB and the minor leagues was 8.95 (set with the Reds in 2019). In 2020, Mahle struck out 60 batters in 47.2 innings for a whopping 11.33 K/9. Considering Mahle’s velocity stayed relatively consistent (his fastball velocity went up by 0.6 mph to a 93.9 average), his breakout must have a deeper root cause.


Using the above graphic, we can see that a key change in Tyler Mahle’s approach was the substitution of his curveball in favour of a slider. Interestingly, the slider was not a new pitch for Mahle. He threw it in both 2017 and 2018 but had mixed results (14.3% swinging strike rate, .476 xwOBA on contact), which caused him to drop it altogether in 2019 and rely more on his curveball. In 2019, Mahle threw his curveball 22.4% of the time, but the pitch also got hit hard and was worse at inducing whiffs than his slide had been.

In an attempt to improve his results, he threw just eight curveballs during the entire 2020 season and re-engineered his slider instead. By adding over 100 RPM to the pitch and decreasing its downward movement, his slider became nasty. The pitch generated a 19.6% swinging strike rate and received much better results when put in play than the previous version. Due to his comfort with the pitch, Mahle was able to throw it 32.4% of the time.


Another change was the sudden dominance of his high 4-Seam fastball. Since Mahle’s fastball did not see an uptick in high strike zone usage or any major velocity gains, the next place to look is movement. In 2019, Mahle had a spin rate of 2161 RPM and 87.8% of that spin contributed to pitch movement. These numbers are not great, but there was an even bigger problem. Most of Mahle’s spin was resulting in horizontal movement, as opposed to vertical movement. As demonstrated in my third article, vertical movement (less drop for fastballs) induces more whiffs which generally leads to more success.

Likely already knowing this, Mahle was able to improve every aspect of his fastball this season. His velocity (+0.6 mph), spin rate (+228 RPM), and active spin rate (now 99.9%) allowed his fastball to drop 3.7 inches less compared to 2019. For the first time in his career, Mahle now had above-average vertical movement on his fastball which allowed it to stay “on plane” longer than ever before, causing the pitch to be harder to hit when thrown high over the plate as seen by his 17.0% swinging strike rate and .330 xwOBA on contact.

The final noticeable change in Tyler Mahle’s approach was the regression of his splitter. In 2019, Mahle’s splitter was dominant and received nearly identical stats to his 2020 high 4-Seam fastball. However, after adding 305 RPM to his spin rate and spinning the ball 23.9% more efficiently in 2020, his splitter’s swing and miss results declined significantly. Since the splitter is also known as a “split-finger fastball”, it makes sense that it shares some fastball characteristics. Mahle throws the splitter with a similar grip and ideally, the same arm slot. These features allow the pitch to generate a small amount of backspin which makes it hold its plane until diving towards the dirt at the last second.

Unfortunately for Mahle, increasing his spin rate and spin efficiency also increased the amount of backspin on his splitter, which caused it to hold its plane much longer than average, resulting in his splitter dropping 6.6 inches less than the year before and missing fewer bats. Although his version of a splitter was hard to miss, it was nearly impossible to do anything with when hit into play, as shown by its .261 xwOBA on contact. If Mahle can take some more spin or speed off his splitter to recapture the pitch’s 2019 dominance, he will have a third legitimate weapon in his arsenal which should help him build off his solid 2020 season to have an even better 2021.


Photo credited to Getty Images

Kevin Gausman

Like Dylan Bundy, Kevin Gausman is another former member of the Baltimore Orioles’ contending team of the mid-2010s. Oddly enough, he was also picked 4th overall by the Orioles one year later than Bundy during the 2012 MLB Draft. Although he had some good seasons, he never quite lived up to the expectations of such a high pick. As the Orioles started to fall out of contention in the AL East and move on from their core players, Gausman was one of the first pieces to go. 

At the 2018 trade deadline, the Orioles sent Gausman to the Atlanta Braves along with Darren O’Day for a package of decent-looking prospects. Gausman dominated the rest of the year by putting up a 2.87 ERA in ten starts for Atlanta, although his peripherals suggest this success was unsustainable. After starting 2019 with the Braves, things didn’t go so well. In his sixteen starts with the Braves in 2019, Gausman had a 6.19 ERA and eventually dropped to waivers. The Cincinnati Reds claimed him and used him in the bullpen the rest of the season. After signing a one-year deal in San Francisco, Gausman had a dominant 2020 season.


By increasing the usage of his splitter and high 4-Seam fastball, Gausman was able to generate a career-high 11.92 K/9 rate in 2020 after setting a previous career-high rate of 10.03 in 2019. Although Gausman had swing-and-miss stuff in 2019, he was lit up to the tune of a 5.72 ERA, mainly because he still threw his 4-Seam fastball low over the plate at a 22% rate.

By reducing this rate by 10%, Gausman induced softer contact overall, and he made up for his decline in low fastball usage by increasing the usage of his more effective pitches, allowing him to achieve a 3.62 ERA, and career-highs in expected ERA (3.49), xFIP (3.06), and SIERA (3.24) in 2020. Gausman – now a free agent – has likely pitched himself to a huge contract this offseason.


Photo credited to Bill Streicher — USA Today

Drew Smyly

The San Francisco Giants and their Canadian President of Baseball Operations, Farhan Zaidi, got another free agent steal last offseason by signing Drew Smyly to a 1-year contract worth $4,000,000. Smyly, a former top prospect with the Detroit Tigers, was one of the key pieces involved in the trade that sent David Price from the Tampa Bay Rays to the Tigers back in 2014. After spending two seasons in Tampa, Smyly was traded to Seattle for several prospects including current Rays starter, Ryan Yarbrough

Unfortunately, Smyly got hurt before the season started and underwent Tommy John surgery which ended his season. In 2018, Smyly signed with the Cubs but spent the entire year rehabbing his injury, and for the second consecutive year, he failed to throw a pitch at the major league level. He was then traded to the Texas Rangers and spent some time with the Milwaukee Brewers and Philadelphia Phillies. In all, Smyly finished the 2019 season with an ugly 6.24 ERA. Despite not having an ERA below 4.50 since 2015, the San Francisco Giants saw enough potential in Smyly to give him another shot.


Since Drew Smyly hadn’t thrown a pitch in the big leagues between 2016 and 2019, it made sense to only compare his 2020 season to last year, as the approach of the game can change a lot in that span (his 91 mph average fastball velocity during his prime years used to be average but now it is well below). In 2020, Smyly was incredible. Although he only pitched 26.1 innings, each of his pitches performed better than the previous season. Smyly’s 0.68 HR/9 rate was his best mark as a starting pitcher, and his 14.35 K/9 set a new career-high. His 2.56 xFIP was also the best mark of his career. 

So what did Smyly do differently in 2020? The most important change he made was increasing his velocity. Smyly’s 93.8 mph average fastball velocity in 2020 was the hardest he had ever thrown, and with velocity comes added bonuses. His fastball spin rate jumped by 163 RPM and his fastball had 1.9 fewer inches of drop on average. His velocity spike also carried over to his other pitches. Both his cutter and curveball saw a velocity increase of 2.6 mph on average.

Similarly, their spin rates also jumped. Without any changes in the movement profile or active spin percentage, these numbers are likely the result of his increased velocity and might be inflated slightly due to his low amount of innings pitched. Additionally, Smyly threw more curveballs than ever before in 2020, which also ended up being his best pitch, helping to produce his high strikeout rate. 

Like Gausman, Smyly will likely be due for a significant salary increase when he hits the free-agent market in the offseason. If this is the case, the San Francisco Giants should be a team to monitor this offseason. They fell just short of the playoffs in 2020 and will likely have two holes to fill in their rotation. If the Giants’ findings of Smyly and Gausman were due to the skill of their management and not a fluke, we could see a few more career resurrections coming from “the Bay Area” in 2021.


Photos credited to Getty Images

A few more 2020 breakouts

Mike Mayers

Like 2020 home run leader Luke Voit, 2020 playoffs breakout star Randy Arozarena, and Seattle Mariners’ ace Marco GonzalezMike Mayers is a former St. Louis Cardinals castoff. The Los Angeles Angels claimed Mike Mayers off waivers after he posted a 7.03 ERA in 80.2 innings. By dropping his fastball usage by nearly 20% and replacing it with a lethal cutter, Mayers posted a 2.10 ERA, 2.40 expected ERA, and became the Angels’ closer at the end of September. Entering the 2021 season, the Angels look set to field a dangerous lineup, a true number-one starter, and an elite closer.

Jalen Beeks

Picked up by the Tampa Bay Rays for Nathan Eovaldi in 2018, Jalen Beeks struggled to start his major league career. Used as both a middle innings reliever and a “bulk starter” (a speciality of the Tampa Bay Rays), Beeks posted a 4.70 ERA in 155.0 innings coming into 2020. After narrowly making the Rays bullpen out of the MLB’s 2020 “Summer Camp”, Beeks was a completely different pitcher. 

His 4-Seam fastball velocity averaged 1 mph more than in 2019 and it generated 1.8 fewer inches of drop. However, Beeks\’ biggest change was his approach. Beeks removed his curveball from his arsenal, and for the first time, he threw his changeup (43.7%) more than his fastball (42.4%). With his changeup always being his best pitch results-wise, Beeks produced a 3.26 ERA and a 2.61 expected ERA which was in the top 5% of the league. Beeks struck out 12.10 batters per game, walked 1.86 batters per game, and surrendered just 0.47 HR/9. 

Amazingly, Beeks accumulated a 0.7 WAR in just 19.1 innings as a reliever. Unfortunately, Beeks sprained his elbow mid-season, which means the Rays could have been even deadlier this year. Despite the low innings count, Beeks’ breakout looks real, and his .400 BABIP (batting average on balls in play) indicates that he could be due for some positive regression next season (BABIP is a volatile stat which usually settles between .300 and .330 for every pitcher when a large enough sample size is provided). If Beeks is real, the Rays will once again be a force in the AL East.

Jordan Romano

Born in Markham (just outside of Toronto), Jordan Romano will likely become a fan favourite if he continues his 2020 dominance. While Romano was a starter in the minors, he was never a top prospect. The Chicago White Sox drafted Romano in the 2018 Rule 5 Draft and immediately flipped him to Texas where he got a shot at making the Rangers roster in Spring Training. Romano pitched decently for the Rangers with a 3.86 ERA in 9.1 Spring Training innings, but the Rangers didn’t add him to their 25-man roster and sent him back to Toronto.

After struggling to the tune of a 7.63 ERA in 2019 with the Jays, Romano went to work in the offseason, using a Rapsodo machine to scrutinize and improve his pitch design and mechanics. The new-looked Romano increased his average fastball velocity from 94.6 mph to 96.5 mph, which resulted in his fastball dropping 2 inches less. He also sharpened his slider and threw it 23% more while simultaneously throwing his fastball 23% less.

With his slider usage now at 59.9%, Romano put up a minuscule 1.23 ERA, 2.40 xFIP, and 2.74 expected ERA. Romano struck out nearly the same number of batters in 2020 as he did in 2019. However, his fastball got crushed in 2019, so reducing its usage by 23% dropped his HR/9 rate from 2.35 to 1.23. Relying more on his slider helped his command as his BB/9 dropped from 5.28 to 3.07. With Ken Giles being a free agent and likely out for all of 2021, Jordan Romano may be his heir next season.

Jake Diekman

At 33 years old, Jake Diekman could be the definition of teaching an old dog (from a baseball perspective) new tricks. After watching a video of Chaz Roe’s frisbee-like slider (another Rays pitcher) during the offseason, Jake Diekman decided to replicate it. His previous slider had just 5.9 inches of horizontal movement which was 0.1 inches fewer than average at his velocity and release point. In 2020, he more than doubled his slider’s horizontal movement to 14 inches which now sat at 7 inches more than average. 

When contacted, the pitch’s xwOBA dropped from .319 to .199 and overall, Diekman posted a career-low 0.42 ERA which was supplemented by a solid 2.59 expected ERA. Diekman has always had command issues, and 2020 was no exception. However, his new slider and a stronger emphasis on throwing his fastball high allowed him to set a career-best 13.08 K/9. The beautiful thing about Diekman is that even as a left-handed pitcher, his numbers are equally as good against right-handers, which will give him immense value in the Oakland bullpen if the MLB keeps the 3-batter rule in place, going forward. 

Pitchers with untapped potential

Once again, this section won’t include 2020 numbers as some of the game’s best pitchers didn’t have their best “stuff” due to the lack of preparation time and the disruption of their pre-season routine. However, there are many pitchers who qualify for this list so the ones included are guys who would really benefit from making adjustments.

Vince Velasquez


Vince Velasquez has a deep selection of pitches in his arsenal. He possesses a great changeup, an average slider, and an average curveball. His best pitch, though, is his 4-Seam fastball which is most effective when thrown high due to its low amount of vertical drop. The problem with his approach is that he doesn’t throw his best pitches nearly often enough. Velasquez has the velocity and movement to dominate hitters if he uses his fastball properly as shown by his 17.5% swinging strike rate. His 1.43 HR/9 suggests he has trouble keeping the ball in the yard, but his high fastball xwOBA on contact of .311 should suggest the opposite.

If Velasquez wants to dominate hitters, he must stop throwing his 4-Seam fastball in the low part of the plate. Velasquez throws low on 20.8% of his fastballs, and 14% of them have been down the middle. With the way batters crush the low ball now, this explains his home run issues. His 2-seamer/sinker is worse than his high 4-Seam fastball, but with a 10.1% swinging strike rate and only a 6.4% usage rate, he might be able to surprise hitters if he keeps it but lowers its usage. Velasquez has a great arm and an incredible amount of potential waiting to be optimized. With the possibility that the Phillies not extending him via arbitration and his team control expiring in 2022, Velasquez would be a sneaky pickup if he finds the right team and is willing to change his approach.

Trevor Williams


I feel bad for any Pirates fans reading this article. Not only have they witnessed the breakouts of Gerrit Cole, Tyler Glasnow, and Charlie Morton, they may have another starting pitcher in the same situation. Trevor Williams doesn’t quite have the same arm as Vince Velasquez, but he does have a similar profile. Williams has some good pitches but has been plagued by his heavy reliance on his sinker and low 4-Seam fastball. Interestingly, under the Pirates’ management in 2020, Williams did heavily cut down on his sinker and his low 4-Seam fastball but still put up a 6.18 ERA in 11 starts. The problem was that Williams still threw his high fastball at nearly the same rate while instead increasing the usage of his slider and changeup, allowing him to set a new career-high K/9 at 7.97, but batters now teed off on him (2.44 HR/9). 

Williams’ fastball had 19.2 inches of drop in 2020, which was 2.7 inches below average due to his incredibly low active spin rate of just 65.4%. If a team like the Astros who can make subtle throwing motion tweaks were to get their hands on Trevor Williams, his fastball could become a lot better. Because of the shortened season and an injury, Williams also got some bad luck. His wOBA on Contact of .435 was significantly higher than his expected wOBA (xwOBA) of .369 which is below his career average. Since these numbers are based on exit velocity and launch angle of the batter’s swings, it is fair to write this off as an issue of sample size. In a full season of games and with some adjustments to his fastball made, Trevor Williams still has the potential to become a quality starting pitcher.

Kyle Crick


Sadly, I am not done picking on the Pirates. Kyle Crick has the fastball velocity and the slider to dominate hitters. All he has to do is leverage these pitches more. His sinker and low fastball don’t get crushed, but they do get hit harder than his other offerings. When combined with the fact that both pitchers don’t fool hitters, it would make sense to reduce their usages. In 2020, it appears Crick tried doing that as he threw his slider 54.8% of the time, which is a step in the right direction but nothing more though since Crick got injured and only pitched 5.2 innings this year. 

It is also worth pointing out that his average fastball velocity dropped from 95.3 MPH in 2019 to 90.9 MPH this year, which could explain why he threw his slider so much, and because of his injury. For what it’s worth, Crick gave up just one run in those 5.2 innings with seven strikeouts so if this was a new approach for him it was working. Depending on whether his velocity comes back and if his slider usage is here to stay, Crick could become a hot commodity at next year’s trade deadline if the Pirates continue to rebuild.

Antonio Senzatela


The Colorado Rockies are a team that is known to be lacking from an analytics perspective. They also deal with “The Coors Effect” as their ballpark, Coors Field, is built at the highest elevation of any stadium in baseball, making fly balls carry further which emphasizes the importance of optimizing their pitchers to allow weaker contact on balls in play and less contact in general. Antonio Senzatela is one of their pitchers who is waiting to be optimized. Senzatela averages 93.9 MPH with his fastball, so there is no excuse for his 6.36 K/9. He also owns a decent changeup, a good slider, and a great curveball. Despite his velocity, Senzatela’s fastball has too much drop, which is why his swinging strike rate was just 9.4%, which is mainly due to his 61.2% active spin rate. 

However, his fastball didn’t get hit hard when he threw it high. When he threw it low, on the other hand, his fastball got crushed and generated a swinging strike rate of less than 1%. Instead of throwing his great curveball (7.4% usage rate), Senzatela threw low fastballs 25.9% and belt-high fastballs 15.7%. This is not a good idea when pitching at Coors Field. In 2020, Senzatela had a 3.44 ERA, but his strikeout rate was in the bottom 4% of the league, and his expected ERA of 4.61 suggests that he won’t produce that high of an ERA next year without making significant changes. The good news is that Senzatela did reduce his fastball usage by 6% and replaced it with his slider, allowing him to induce the weakest contact rate in his career (.317 xwOBA). If Senzatela can miss more bats by throwing his best pitches, he should have a lot more success.

Jeff Hoffman


Another Colorado Rockies pitcher with potential is Jeff Hoffman. As a former 9th overall pick by the Blue Jays in 2014, Hoffman was traded to Colorado in the Troy Tulowitzki deal. In Colorado, he has not looked like the top prospect he once was, as his pre-2020 career ERA of 6.11 was well-below replacement level considering he had pitched over 200 innings. Like Senzatela, Hoffman’s fastball has enough velocity to miss bats, yet his K/9 is below league average. Oddly enough, both Hoffman and Senzatela have the same arsenals and the same problems. Hoffman throws far too many fastballs either low or down the middle of the plate. Hoffman’s fastball isn’t the best as he gains much more horizontal movement than vertical, but it’s still miles better when thrown high than low. 

He owns a few weapons, with a curveball that is hard to barrel and an underutilized slider which has had success in the past. Despite having a swinging strike rate of 16.8%, Hoffman threw only 12 sliders in 2019 and got rid of the pitch completely in 2020. In 2017, his slider had a 21.4% swinging strike rate. The reason for his slider’s success that year was likely the pitch’s spin rate. At 2727 RPM, his slider spun nearly 200 RPM more than any other season he has had and produced 6.7 more inches of drop than the average Major League slider at his velocity. Despite not having the same movement any other year, Hoffman’s slider has still produced solid numbers, and in 2019, the pitch had a spin rate of 2486 RPM which was above average. Since Hoffman ranked in the bottom 1% of baseball in hard hit percentage and exit velocity allowed, he should consider implementing changes as he will run out of opportunities soon. That starts with throwing fewer fastballs low in the zone, but revisiting his slider could be the ultimate wild card.

Jon Gray


Yup, another Colorado Rockie. Jon Gray is undisputedly the best of all three Rockies on this list. He is a former 3rd overall pick and has averaged 95.3 MPH on his fastball throughout his career. Gray also owns two seasons with an ERA under 4.00 which is impressive for a starting pitcher, considering he has played half his games in the most hostile pitching environment in baseball. However, Gray’s ultimate potential is being held back. Once again, he is throwing far too many fastballs below the top of the strike zone. 

His high fastball is hard to do anything with, and he pairs it with an outstanding slider that dominates hitters. Gray’s curveball and changeup are also useful pitches, but he doesn’t throw them nearly enough. Judging by the difference between his ERA and xFIP, Gray has been unlucky thus far in his career, but it is normal for pitchers in Colorado to underperform their expected stats. Based on the movement of his pitches and his velocity, Statcast compares his current profile to that of 2019 Max Scherzer and 2019 Brandon Woodruff, whom both dominated during those seasons. If Gray wants to take the next step towards becoming a legitimate ace, he must limit the number of low fastballs he throws and lean on his secondary pitches instead.

Austin Brice


To some people, Austin Brice is a AAAA pitcher who is only in the big-leagues because the teams he has been on have been bottom-dwellers. Most fans have probably never heard of the former Miami Marlins and Cincinnati Reds relief pitcher. However, he appears to have intriguing potential if used properly. From 2016 to 2018, Austin Brice threw his sinker 45.1% of the time. Unknown to him, his curveball and 4-Seam fastball (when thrown high) generated nearly double the swinging strike rate while having very similar results when hit into play.

This all changed in 2019 when Brice was able to cut his sinker usage by over 25% and doubled the combined usage of his curveball and high 4-Seam fastball. This arsenal change upped his K/9 by 1.56 and got his ERA down to 3.43 as these pitches got great results when hit in play. However, Brice still used his sinker 19.5% of the time in 2019, which is noteworthy because it was still his worst pitch. If Brice can manage to increase his high fastball usage and drop his sinker, he could become an elite relief pitcher. I thought this would be the plan for him in 2020 considering that the Boston Red Sox (second in high 4-Seam fastball usage over the last five years) made a trade for him in January of 2020, but Gray increased his sinker usage to 27% in his first year with the Red Sox. As a result, Gray ended up with a 5.95 ERA and once again, and his 4-Seam fastball was effective. Hopefully, he will implement this change before his career is wasted.

Austin Adams


Austin Adams is primarily a two-pitch pitcher for the San Diego Padres. Having so few options could be a red flag for some people as it is easy to become predictable. However, pitchers like Josh HaderNick Anderson, and Aroldis Chapman have recently made it work. Speaking of Hader, both he and Adams have 60 out of 80 graded fastballs and good sliders. Interestingly enough, Adams’ slider (graded 70/80) is better than Hader’s (graded 55/80). Adams also owns a career 3.34 ERA in the minor leagues. 

So what can Austin Adams do to get even better? His 4-Seam fastball has been crushed over the low portion of the plate. That .623 xwOBA is close to the same result he would get from walking a batter every time he threw his fastball in that location. Even though his 12.7% usage rate is pretty small, it jumps up to 17.6% of ineffectiveness when you include his rarely-used sinker which also gets hit hard (.471 xwOBA). If Austin Adams can cut down on these two pitches, even more, he could become a perennial sub-3 ERA pitcher. The only thing holding him back at that point would be his ugly walk rate, but it would make the Nationals and Angels regret trading him away. 


Pitching philosophy in baseball is changing. Low 4-Seam fastballs and sinkers are no longer resulting in weak contact and rarely fool hitters. The launch angle-based approach by hitters allows them to elevate these pitches. As a result, baseball’s top pitchers are becoming more dependent on their high heat and pitchers with great breaking balls are starting to use them as their primary pitches. However, not every team has been quick to adapt to this new approach. The Pittsburgh Pirates took until the end of 2019 to fire their General Manager, Neal Huntington, and hopefully put an end to their “pitch to contact” regime. The Pirates possessed many great pitchers over this past decade but have held them back with their own failed philosophies. Another team in the same position is the Colorado Rockies. Until they figure this out, they will continue to waste their talented lineup of hitters with poor pitching performances. 


Unfortunately, this is the end of my Throwing By the Numbers series. I would like to thank you for reading my articles, and I hope this was somewhat interesting to you. Together, we covered several aspects (probably too many) of the complexity of pitching successfully in the Major Leagues. I hope you learned something new or at least saw the game from a new perspective. In any event, I figured I would leave you with my three takeaways from this series:

  1. High Fastballs > Low Fastballs

  2. Gerrit Cole is good at baseball

  3. Russell Martin is the MLB’s all-time ERA leader


Statistics retrieved from Fangraphs, Baseball Savant, Baseball Reference,, Salary Figures from Spotrac

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