Why hitters are making contact on Taijuan Walker’s splitter, and how the Phillies plan to fix it

Taijuan Walker’s splitter is his most important pitch. He threw it 33.2% of the time last year, more than anything else in his arsenal. This year, he’s been leaning more on his sinker and sweeper because the splitter hasn’t been as effective.

The numbers back that up. Last year, hitters hit .205 and slugged .295 on his splitter, a pitch that induced whiffs at a rate of 24.4%. This year, that number has ballooned to .515, with a .758 slugging percentage and an 11.3% whiff rate.

Despite that, Walker says the splitter remains his primary weapon. Which means he and the Phillies have to figure out to how to get it back to what it once was. Walker believes he has made some progress in that regard.

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He threw a bullpen on Wednesday in San Francisco and tried out a slightly different grip on the pitch. He said the splitter had better action in that bullpen and looked sharper later. He is going to try it out to see how it feels, with the hope that a small adjustment can lead to big results.

“I’ve been tinkering with the new grip right now to see if that can kill some speed just for now,” Walker said. “During the bullpen, I felt really good. Just kind of killing some spin on it. So just kind of messing with it. And it’s feeling good.

“I was getting pretty good blister from the splitter [this year]. So I’ve just been working on a different kind of splitter grip that kind of has the ball kind of slipping out of my fingers. So coming off like a two-seam. That’s what I’m working on.”

Walker said the grip he used last year also gave him minor blisters, but they weren’t as intense as the blisters he gets now. He isn’t sure why that’s been happening, but he hopes the grip can help address the issue.

He also hopes it will help him locate his splitter better. Walker thinks the main reason he has been hit hard on that pitch is that he is leaving it up. Because he isn’t throwing as hard, location has made keeping the ball down more important. Walker is averaging 91.4 mph on his four-seam fastball and 86.2 mph on his splitter.

Last year, there he was averaging 92.8 mph on his four-seam fastball and 87.9 mph on his splitter.

“[It’s all about] location,” Walker said. “Just leaving it up in the zone, I think that’s the biggest thing. My fastball is 91-92 mph and my splitter is 87-88. That speed differential when we leave it up, it’s not gonna really fool any hitters. And you know, obviously if my fastball is 94 mph, then splitter would be 87-88 mph, which works better. But this differential is too close right now.”

Pitching coach Caleb Cotham agrees that keeping the ball down will be paramount for Walker.

“I think it’s the most important thing,” Cotham said. “I think it’s more important than shape, how much sink, how late it breaks. The most important thing for his pitches is for them to get down. Because at the end of the day, they’re not really great get-me-over-strike pitches. It’s kind of like sliders, hard sliders, in a sense. You want to present them to where they go strike to ball. But also you want to create strikes with them. So you want to be down.

“Left-handed hitters are hitting [the splitter] better than last year, but a lot of those pitches are top of the upper third, mid-thigh, mid-thigh away, so getting the ball down, we know that helps. He’s working hard at it.”

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Trea Turner (left hamstring strain) took some ground balls on the field on Friday afternoon and did some light jogging. He also hit in the batting cage. Manager Rob Thomson said he is unsure when Turner will be ready to run the bases, which is the next step in his rehab progression.

The Phillies have an opportunity to shake up the rotation after the London series, if they want to. They have two off days before the two-game set in London and one off day after it. Thomson said they’ve talked about how they want to line up their starters in London but expects his pitchers to stay in rotation, for now.

“There’s going to be a lot of days off, which is a good thing right now for our rotation,” Thomson said. “We’ve put a lot on them. They’ve logged a lot of innings. At this point, I wouldn’t be surprised if we stay right in rotation. Some guys are going to get six days off, some will get seven, which, at this point, might be good for them.”

Zack Wheeler does not enjoy pitching on extra rest and plans to accompany the team to London. He isn’t lined up to start right now, but he could take someone’s spot — perhaps Walker in the series finale — if the Phillies choose. Nothing is set in stone yet.