The Relief to Starter Pipeline

An unorthodox role change could yield success in 2024.

It’d be neat to turn every elite reliever into a starter. 100 mph splinkers from Jhoan Duran for five innings? Sign me up.

But that’s not the reality for most pitchers. There’s a reason pitchers end up in the bullpen. It could be ability (command, lack of enough pitches, stamina) or team context (i.e., the Dodgers and their 12 starting pitchers on the team/IL), but it’s often a mix. Once pitchers fall into the reliever mold, breaking out of the max-effort short outings is hard.

Many of baseball’s recent strategy changes have bucked conventional wisdom, and there seems to be no stopping in 2024. Four pitchers have started 2024 attempting to make the jump from reliever to starter: Garrett Crochet, Jordan Hicks, A.J. Puk, and Reynaldo López.

These four pitchers have a unique path to becoming a starting pitcher in 2024. Three of them have professional starting experience: A.J. Puk started as a pitcher at the beginning of his minor league career, Reynaldo López started 96 games from 2016 to 2021, and Jordan Hicks made eight starts in 2022. On the other hand, Garrett Crochet had no previous starting experience. He was not a consistent starter at the University of Tennessee, where he started only 36% of his college appearances.


Garrett Crochet


Crochet has been the star of this group so far, pumping out two quality starts in his first three starts. He’s taken his arsenal from his time relieving and extended it to 90 pitches, which is almost a unicorn transition. Maintaining fastball velocity while improving command significantly when stepping up to a starter’s workload is unusual on all fronts, which is why the biggest test for Crochet is the longevity of these improvements.

The upper-90s fastball is the base of the arsenal, as Crochet throws it 51% of the time. Although the pitch has average ride (16 inches of iVB) and average run (7 inches), Crochet’s 7.2 ft of extension helps the elite velocity get whiffs 33% of the time. As for the location, he’s maintained his career 53% zone rate on the fastball while elevating it at an above-average rate. The return on the pitch is 23% ICR%, 34% CSW%, and .095 AVG against, making it a dominant force.

Crochet’s main secondary offering is the sweeper, which he throws 31% of the time. Despite the extreme platoon splits to opposite-handed hitters, Crochet throws the sweeper more frequently to RHB. Unlike most sweepers, Crochet appears to be trying to throw this pitch directly in the zone. It has a 76th-percentile zone rate, which is Crochet essentially asking hitters to try and hit it. The result is a 34% CSW% and an elite 12.5% ICR% on the sweeper, though the strong batted ball suppression may regress throughout the season.

The last two pitches that fill out the arsenal are a cutter and changeup. The cutter has been used as an effective first-strike pitch that can get called strikes, and the changeup has been deployed a handful of times to RHB.

Crochet’s key to success throughout the season is his ability to maintain his velocity and command. He has already demonstrated his ability to pitch deep into games and possesses a high ceiling if he can avoid issuing walks throughout the year.


Jordan Hicks


Jordan Hicks already made one attempt to start at the big leagues, but this one seems a bit different after the Giants inked him to four years, $44M contract with the intention of Hicks being a starter (cite).

Hicks, like Crochet, is very dependent on his fastballs. Hicks throws a sinker 55% of the time and a fastball 8% of the time. The sinker gets 17 inches of run at 95.6 mph, and Stuff+ grades the pitch at 106. It is used as a contact-inducing pitch as it lacks in called strikes and whiffs (26.6% CSW%) but holds a 22.7% ICR%, ranking in the 87th percentile. Hicks has only deployed the fastball against lefties in 2024, but its command has been erratic.

He has two new-ish secondary pitches: a sweeper and a splitter. The sweeper debuted in 2023 with solid results and has continued in 2024. It’s yielded an above-average rate of whiffs and called strikes, leading to a 35.1% CSW%. The sweeper is thrown 35% of the time to RHB and 10% to LHB, as Hicks turns to the splitter as his third pitch for both-handedness hitters and the fastball for a fourth against LHB. The splitter is a new weapon for Hicks this year, and it is filthy:

It grades out at 134 Stuff+, the sixth-best splitter in baseball so far (minimum 5 IP). The pitch has 2.3 inches of drop, which is 95th percentile, and is effective for both called strikes and whiffs.

Hicks’ most significant step forward this year is his command, which starts with a 9% increase in sinker zone rate. He’s walked only one batter in 12 innings to start the year, which is a significant change from his career 12.3% BB%.


A.J. Puk


A.J. Puk Stats

A.J. Puk is the lone pitcher on this list not to start 2024 strong as a starter. He has a 5.91 ERA across three starts, and the excitement from Spring Training is all but gone. He initially impressed by striking out six Yankees in three Spring innings, but his first two regular season starts have been far removed from that promising Spring performance.

Puk has four pitches: a fastball, sweeper, sinker, and splitter. The fastball, which was elite in 2023, has taken a step back in 2024. Puk raised his release point to better command the splitter, negatively affecting the fastball’s strong shape metrics. It used to have one of the best attack angles in baseball, a 1.5 HAVAA, but the changes have led to a 0.6 HAVAA, one of the worst. He also has yet to show command on the fastball, with a 37% zone rate.

The sweeper and splitter have been sub-13% SwStr% pitches, which means that improved fastball command may not bring whiffs to other pitches. Even in the best outing of the year (4.2 IP, 1 ER), Puk only had two strikeouts, five walks, and a 22% CSW%. This limits Puk’s ceiling in the future, but the command will likely improve at least slightly. Otherwise, Puk may find himself back in the bullpen, regardless of the situation in Miami.

Reynaldo López


Lopez’s first start resulted in him getting outdueled by former teammate and current reliever-to-starter pitcher Garrett Crochet, but that’s not to say the performance was poor. Six innings with one earned run, four hits, two walks, and five strikeouts is a solid day at the park.

But Lopez’s stuff is merely average compared to the highs of Hicks and Crochet or the lows of Puk. The fastball returned a 25.9% CSW% on 65.9% usage, an underwhelming return of called strikes and whiffs. It has 16.8 inches of iVB and a 1.0 HAVAA, meaning it has slightly above-average vertical movement and approach angle. This fastball can be the base of a strong arsenal, but the slider only got two whiffs on 20 swings in one start. Batters made contact with the slider 80% of the time, which got outs but did not inspire confidence for the future.

Lopez’s second start displayed a slight change in usage, which is why these early usage trends aren’t always telling. He went with elevated fastballs and more curveballs instead of sliders, which resulted in a strong six innings of shutout ball. The curveball yielded a 40% CSW%, and it could be a tool to help Lopez get deeper into games in the future. While the fastball was successful here, it still underwhelms in pure stuff.

Nate Schwartz

Nate is currently writing for the Going Deep team at Pitcher List. He is a lifelong St. Louis Cardinals, devil magic, and Matt Carpenter salsa supporter. You can follow him on Twitter/X/whatever @_nateschwartz. Left-handed pitchers make him happy.

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