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3 Starting Pitchers Poised For A Breakout

Springtime in baseball is rife with expectation for pitchers. It’s a new year, and over the offseason, players have been working on their craft, whether that be tweaking their pitches, adjusting their mechanics or getting their minds right. Spring training allows players to practice those changes in a simulated setting, but it’s not until a ways into the regular season that we truly know what they have.

For this reason, I can pinpoint what I find compelling about a player, but in the end, it all comes down to the respective pitcher’s execution and optimization of the tools at their disposal. With that said, here are three pitchers I consider to be on the precipice of a breakout going into the 2022 season.

Mitch Keller

Perhaps the most obvious breakout candidate is Mitch Keller of the Pittsburgh Pirates. Keller spent the offseason working at Tread Athletics, a development company focused on pitchers, with a goal of relengthening his arm action to get his velocity back. Keller had averaged 95.4 miles per hour on his four-seam fastball in 2019, but since he shortened his arm swing two years ago, he was sitting below 94 mph.

Not only did he get his velocity back, but he looks set to be one of the hardest throwing l starting pitchers in MLB. Consider some metrics from one of his offseason bullpens:

Perhaps most notable is that Keller has pushed his fastball velocity up to 100 mph — almost two ticks harder than he’s pitched at any point in his career. How you describe Keller’s 2021 fastball depends on whether you consider it by its 15.7 induced vertical break or its -5.26 zone-adjusted vertical approach angle in 2021, according to Nathaniel Plotts. By the former, it’s a fringe dead zone fastball — it ranks in the 40th percentile of qualified four-seam fastballs by IVB, according to Alex Chamberlain’s pitcher leaderboard — while it’s too steep by the latter. The good news? If Keller is sitting in the mid-to-upper 90s, he’ll be able to gas past concerns about his fastball shape.

Almost the entirety of Keller’s repertoire has changed as well. He’s retained his old gyro slider — making it the only true holdover from last year — but he’s also added a slider in the low-80s with elite horizontal break, making him a card-carrying member of the sweeper revolution that’s rapidly spreading throughout MLB. The idea is that sweepers generate a lot of whiffs, but when they’re not missing bats, they have the tendency to induce a lot of pop-ups, which are exceedingly pitcher-friendly. So if Keller has a feel for the new slider, it could conceivably become one of the better pitches in all of baseball.

That’s nothing to say of his improved changeup — which has looked special at times with plus depth at 92 mph, and with 18 inches of run — or his curveball, which he has bumped from the mid-to-high 70s into the low 80s. It appears that Keller has at least three distinct pitch shapes with glove-side movement, with a hard slider around 90 mph, a sweeping slider in the mid-80s and a curveball in the low 80s.

It’s unclear what metrics are most indicative of what his pitches will look like going into the regular season, but there’s a legitimate chance at five distinct, usable pitches. To throw 100 mph or add a sweeper would have been enough to warrant a breakout. To do both? Keller seems like as much of a slam dunk as it gets.

Oh, and as for comps? Pirates pitching coach Oscar Marin sees similarities between Keller and Joe Musgrove, while Devin Hayes of Tread Athletics likens him to Gerrit Cole

Logan Gilbert

Speaking of revamped pitch arsenals, Logan Gilbert came into spring training with the Seattle Mariners sporting a completely new look. His fastball remains as solid as ever, but every other pitch in his repertoire has changed. 

Gilbert made it a priority this offseason to improve his location, and he’s reshaped his pitches to reflect that. Gilbert’s previous changeup grip — which looks impossible to command — has been shelved completely. His slider, previously 85 miles per hour, has turned into a hard cutter-slider hybrid around 89 miles per hour, and his curveball has gotten 7 miles per hour faster.

The tighter shape of his secondary pitches should signal more competitively located pitches, which Gilbert could use desperately. Gilbert struggled to find the strike zone on three of his pitches in 2021, ranking in the 11th percentile on his slider, 6th percentile on his changeup and 2nd percentile on his curveball among starting pitchers1 in zone percentage, hinting that his fastball was the only pitch he could reliably command.

That’s corroborated by his pitch usage — Gilbert threw his changeup and curveball for a combined 14.6 percent of all his pitches — but also by the effectiveness of all three pitches. His slider and curveball were also wildly ineffective, with rates of called strikes plus whiffs (CSW) of only 24.8 and 13.8 percent, slotting into the 8th and 7th percentiles by their respective pitch types. And while Gilbert’s changeup was more effective compared to the other pitchers who used the pitch, he rarely had the feel for it to throw it with confidence, hence the change in grip.

With a trio of secondary pitches improved in both stuff and command, Gilbert should be able to rely less on his vaunted fastball, which often did too much of the heavy lifting in 2021. That all hints at a pitcher who will be much more consistent — and much less predictable. 

Josiah Gray

Unlike Keller and Gilbert, Josiah Gray of the Washington Nationals hasn’t overhauled his repertoire. In fact, none of his pitches have changed. The difference between him and the former pitchers is that he already has the tools he needs to be successful — he simply hasn’t weaponized them.

Everything starts with Gray’s four-seam fastball. By zone-adjusted vertical approach angle, it’s one of the flattest in baseball (in the 94th percentile in 2021), which means it should be a plus pitch. In some ways, it is — it boasted the highest pop-up percentage of all four-seam fastballs among batted balls — but the dominance ended there. His 22.8 percent called strikes plus whiffs (CSW) rate was one of the lowest for starting pitchers, and while his fastball’s 66.0 strike percentage fared better, it was still below average. It clearly has utility — but perhaps not as a primary offering.

That’s where his secondary pitches come in. Gray has one of the best curveball-slider combos in MLB. Among starting pitchers in 2021 with 500 or more curveballs and sliders thrown, only eight, including names like Corbin Burnes, Max Scherzer and Aaron Nola, bested Gray’s combined 37.0 percent slider and curveball CSW. That’s elite company to be in.

Only 52.0 percent of Gray’s 2021 pitches came on non-cut fastballs, and he has elite contemporaries who have also eschewed four-seamers and sinkers. Shane Bieber, for example, uses his elite curveball-slider combo without throwing his fastball much and, like Gray, has one of the flattest four-seamers in MLB. In fact, they have nearly identical fastball shapes, with Bieber’s fastball performing better than its velocity might suggest due to his plus command.

Odds are that Gray’s heater isn’t going to make up the near-8 point difference in CSW between his fastball and Bieber’s, but that’s all the more reason to fade it in favor of his curveball and slider. Keller and Gilbert may have needed to reconstruct their repertoires, but for Gray, a breakout could be as simple as throwing his fastball less and his breaking pitches more. If nothing else, that would help make the most of the pitcher he currently is.


  1. With at least 100 pitches thrown, for each pitch type.

Michael Ajeto is a writer based in Seattle. His work focuses on baseball analytics and sociocultural phenomena in baseball, and it can also be found at Lookout Landing, Baseball Prospectus and on the podcast It’s Never Sunny in Seattle.


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