Categories: Analysis

So far so good for Zack Wheeler and his splitter

Zack Wheeler is in his fifth season with the Phillies. (Photo by Jeff Robinson/Icon Sportswire)

Like every other Philadelphia Phillies starting pitcher, Zack Wheeler is off to a great start this year. After tossing six scoreless innings on Thursday, the veteran right-hander lowered his ERA on the year to 1.93. Across his six starts, Wheeler has struck out 46 batters in 37 1/3 innings. His 1.3 fWAR entering Friday leads Major League Baseball among pitchers.

It’s no surprise Wheeler is off to a strong start. Since joining the Phillies, he’s transformed into one of the best pitchers in baseball. But Wheeler doesn’t want to just be one of the game’s top pitchers. He would like to officially be recognized as just that.

In March, Wheeler spoke to reporters, including Corey Seidman of NBC Sports Philadelphia. He talked about a new pitch he was adding to his arsenal. The 33-year-old said he hopes that new pitch can help lead to his first Cy Young Award.

The new pitch Wheeler was talking about was a splitter. The thought process behind adding a new pitch to his pitch mix was to help him be better against left-handed hitters.

“I think it just opens up the book a little more to lefties,” Wheeler said back in March. “They did a lot better off me last year than righties did. Me and [pitching coach] Caleb [Cotham] had a lot of discussions this offseason about it. This could put me over the top and hopefully get a Cy Young. That’s what I want to do. If I can take care of lefties like I do righties, hopefully it will take care of itself.”

So far, the early returns on Wheeler’s splitter have been really good. And it’s worked exactly how he’s wanted it to.

According to Statcast data, Wheeler has thrown 73 splitters this year. Against it, hitters have a .100 batting average and .150 slugging percentage. Most of Wheeler’s splitters have been thrown against left-handed hitters. He’s mixed it in against righties, too. Altogether, lefties have hit .203/.288/.344 against him this season. That’s much improved over the .261/.310/.412 slash line they had against him a season ago — the best left-handed hitters have performed against Wheeler during his time in Philadelphia.

Batters aren’t just having a hard time getting hits against Wheeler’s new pitch. They’re also having trouble making contact with it. So far, hitters have a 35.9% whiff rate against his splitter.

Pitchers use splitters in a variety of ways. Wheeler’s splitter is intended to work as a changeup. He’s thrown changeups in the past, but not nearly as much as he’s thrown his splitter this year. Wheeler threw just 13 changeups last year, according to Statcast. He threw 42 two years ago. In both seasons, hitters performed well when Wheeler offered them a look at his off-speed pitch.

Adding a new pitch to his repertoire isn’t new for Wheeler. He added a sweeper last year. Hitters had a hard time hitting it as they had a .198 batting average and .360 slugging percentage against it. So far, his new splitter is on track to be just as good for him.

Pitchers are always tinkering with their arsenals. Sometimes they’ll work on a new pitch during spring training and use it in their first few starts of the regular season. Then, it won’t work and they’ll stop using it altogether. Pitchers are creatures of habit after all. And trying to get comfortable throwing a new pitch is really tough to do, especially at the big league level. That’s what makes what Wheeler did with his sweeper last year, and splitter so far this year, so impressive.

Wheeler has become more than just a hard-throwing pitcher during his time with the Phillies. He’s a legitimate pitcher who doesn’t always need his best velocity to be great. His ability to transform into just that was a big reason the Phillies were comfortable signing him to the big three-year, $126 million contract extension they did before the start of the season.

Some pitchers struggle as they age because their velocity diminishes and they have to find new ways and use different pitches to continue to get hitters out on the fly. Wheeler has seemingly decided to get ahead of that potential downward velocity trend by adding new pitches now.

So far, Wheeler’s new splitter has worked well. It looks like a pitch he’s been throwing for years, not like one he just started throwing not too long ago. Whether or not it helps him win the first Cy Young Award of his career is something we’ll have to wait and see on. For now, his splitter has made it even tougher for opposing lineups to do much damage against the Phillies’ ace.