Can Phillies ace Zack Wheeler get even better with a 'new' pitch this season?

The success the Philadelphia Phillies have enjoyed over the last few seasons can sometimes be unfairly attributed to a relentless offense that can slug it out with the best of them. Often lost in the discussion is the sheer dominance of Phillies starting pitcher Zack Wheeler.

Wheeler is the ace of a Phillies team with playoff goals in mind, and he was recently ranked third most likely to compete for a National League Cy Young Award in a preseason poll conducted by MLB.com.

To put it mildly, Wheeler is very good.

In the forward to a recent interview with Wheeler conducted by FanGraphs' David Laurila, Laurila put into context how dominant Wheeler has been since he put on a Phillies uniform.

"Zack Wheeler has arguably been the best pitcher in baseball over the past four seasons," writes Laurila. "Since joining the Philadelphia Phillies prior to the truncated 2020 campaign, the 33-year-old right-hander has made 101 starts and boasts a 3.06 ERA, a 2.90 FIP, and a 26.7% strikeout rate. Moreover, his 19.3 WAR over that span is tops among his contemporaries."

Sometimes it's easy to take elite performance for granted when it's staring you in the face, but Wheeler has more than lived up to his contract since signing with the Phillies prior to 2020. Along with Aaron Nola, the two co-aces carry the weight of the Phillies playoff hopes on their shoulders. Can Zack Wheeler get any better? That's a question Laurila went into great detail to explore in his recent interview with the ace.

Zack Wheeler is working on adding a new pitch to his arsenal this season

Zack Wheeler is one of many pitchers in Major League Baseball who have undergone Tommy John surgery and come back a better pitcher in the process. Asked about what changed following his return to the mound, Wheeler compared the before and after of his approach to how he throws the ball.

How did his command improve?

“I shortened up my arm action a little bit," explained Wheeler per Laurila. "I used to be pretty long, and I used to curl my wrist behind me — one more thing that kind of had to catch up. The wrist curl was night and day; it was crazy. I didn’t know at the time what I was doing. Shortening up was going to protect me more, and getting rid of that was part of shortening up.”

The added command and return of his upper 90s velocity certainly helped Wheeler take the next step from middle-of-the-rotation power arm to front-of-the-rotation ace on a contending ballclub. Not satisfied to keep throwing the same pitch mix from season to season, Wheeler continues to try to add to his arsenal of pitches by learning new grips.

This season Wheeler has a specific new pitch in mind to add into the mix as he tries to keep hitters off-balance at the plate.

“I’m trying to throw the splitter a good bit more this year," said Wheeler per Laurila. "I’ve always had it — kind of. Five to 10 times a year, maybe. Certain hitters — maybe a Freddie Freeman— where it’s ‘please chase it’ or ‘here it is,’ trying to make them think something else might be coming. But that’s all I’d throw it, and now I’m going to try to throw it a lot more. Lefties hit me a lot better last year, because everything was basically going in to them."

Elaborating on the point, Wheeler was discouraged as a young prospect in the San Francisco Giants system from perfecting the pitch. At this stage of his career, Wheeler has returned to the idea of making the splitter a regular part of his repertoire.

“I wanted to throw it back in the day, in the minor leagues with the Giants," added Wheeler per Laurila." but I was fresh from being drafted and they said, ‘Save that for when you need it, maybe when your stuff starts slowing down a little bit.’ I was like, ‘All right. Cool. Whatever.’ My stuff hasn’t really slowed down, at this moment, but I need something that goes away to lefties. That’s why I want to do it right now.”

Splitters are coming back in style, and Wheeler has had success with it before

A recent article from MLB.com's Mike Petriello details the resurgence of the splitter and sinker as pitches that are regaining popularity with major league pitchers. Once thought to contribute to arm injuries, MLB pitchers like Wheeler have increasingly started to tinker with the pitch more and more over the last few seasons.

Interestingly, Statcast didn't know that Wheeler threw any splitters last season. The tracking didn't pick up any splitters among the six pitches he used in 2023. According to his Baseball Savant page, Wheeler threw 186 splitters in 2018 as a member of the New York Mets. That dropped to 61 times in 2019, and he threw it 27 times in his first season in Philadelphia before it vanished from his arsenal.

In 2018, his 89.7 mph splitter was his best strikeout pitch, with a 42.9 percent strikeout rate and a 31.4 percent whiff rate. But he only used it 6.5 percent of the time. If Wheeler can harness the pitch again this season, we might see him increase his already top-tier dominance over hitters.

After adding the sweeper, which turned out to be his best swing-and-miss and put-away pitch last season, adding a just as effective split-finger is getting us giddy just thinking about the possibilities. He could take his good overall chase (83rd percentile), whiff (68th percentile), and strikeout (75th percentile) rates into elite territory.

We'll be watching closely this spring to see if he starts showing the pitch to batters early.

How good will Zack Wheeler be in 2024? The season has yet to begin, but Wheeler seems ready to hit the ground running with a new pitch that will keep the advantage on his side as hitters gain more tools to decode the pitch mix.