Detroit’s Jason Foley Is Sinking His Way to the Top


Jason Foley has emerged as one of the most reliable members of the Detroit Tigers bullpen, and learning that his four-seam fastball profiled poorly is a big reason why. The 26-year-old right-hander switched to a sinker, and the results speak for themselves. Since debuting with Detroit last June, Foley has a 2.79 ERA and a 3.54 FIP over 36 relief appearances comprising 38-and-two-thirds innings. Throwing his worm-killer 53.9% of the time, he’s logged a 55.3% groundball rate.

Foley, whom the Tigers signed out of Sacred Heart University in 2016, discussed his career-changing repertoire tweak at Fenway Park in late June.


David Laurila: You’ve gone from a non-drafted free agent out of a low-profile college program to a pitcher performing at a high level in the big leagues. How did that happen?

Jason Foley: “I get asked that quite a bit, like — ‘You weren’t good enough to get drafted, so how are you now here?’ — and I think a lot of people are looking for one magic answer, or maybe one magic change that I’ve made. But neither of those are true. It really just stems from hard work and consistency, and from all of the little things that help you get 1% better every day.”

Laurila: That said, a lot of guys who never make it work just as diligently. Have there not been any impactful adjustments, either to your repertoire or your approach?

Foley: “There is one thing that’s made a noticeable change in my career, and that’s starting to throw sinkers. I was always just a four-seam guy coming up through high school, college, and the minor leagues. It’s kind of what you’re taught when you’re young: Here is a four-seam fastball; that’s what you want to throw. But the way that analytics have been coming to the forefront of baseball… I mean, that has really helped me.

“I found out that my fastball doesn’t profile well as a four-seam, and that if I throw sinkers, they have a ton more action to them. Some of that is probably my arm-slot, which is a little bit lower three-quarters. This happened in 2020, and it has propelled my career quite a bit.”

Laurila: When in 2020 did you start working on a sinker?

Foley: “It was in spring training, right before COVID shut everything down. The Tigers brought in a Driveline guy to work with a few of our pitchers in the minor leagues, strictly on pitch design. Mine was specifically where to go with my fastball, and whether to throw four-seamers or sinkers. The guy pretty much told me right off the bat that the two was a significantly better pitch than my four-seamer. From then on out, it’s been a lot more sinkers, and I’ve gotten a lot more groundballs.”

Laurila: Had you ever thrown a two-seamer?

Foley: “It was pretty much the first time I’d thrown one with the intention of continuing to throw it. I’d maybe thrown one or two in games, thinking it was going to work, but that was the first time I realized it was a better pitch. I also understood why it was a better pitch. That made me more confident in throwing it.”

Laurila: And it only took a handful of throws to make that determination…

Foley: “Yes. In that first bullpen, I threw two four-seams and he said, ‘All right, I’ve got those analytics’ — he saw the numbers come up on the TrackMan — and then he said to throw a couple of two-seams. I threw one, and he was like, ‘Yeah, that’s a way better pitch.’

“Outside of velocity, my four-seam was average-at-best across the board in terms of metrics. It didn’t really have much ride. It was mostly just a flat fastball. Being a lower three-quarters guy, kind of from the side, the way the ball comes out, I’m able to get the run-and-sink effect.”

Laurila: Is it more run, or more sink?

Foley: “It probably runs more, but at the same time, it’s kind of a hybrid. It sinks a decent amount, too. It’s usually 15-plus horizontal and floating around six or seven vert, so I get a pretty good combo of both.”

Laurila: Do you throw it with a standard two-seam grip?

Foley: “Pretty much. I kind of go… so, if you’re talking about a standard two-seam, you’re going to go across the two seams, I kind of hug it. I hug the left seam with my index finger, and my middle finger is kind of on the white of the ball. Basically, I only have one finger on a seam.

Jason Foley’s two-seam fastball grip.

“I used to have my middle finger on the right lace, but I would get a blister from that, so I shifted it the other way. Now my index finger hugs the left lace and my middle finger just kind of rests comfortably wherever that may be, which is usually in the middle of the two seams.”

Laurila: Are you basically sinker/slider?

Foley: “For the most part. I’ll mix in changeups to lefties, but sinkers and sliders usually do a pretty good job for me against righties. I will elevate some fours to get swings and misses. Sinkers aren’t the most conducive to missing bats, but I’ll throw them front-hip to lefties and backdoor to righties, and those get me takes for strikes. But I’m cool with getting groundballs. Those have been getting me outs, and that’s what matters.”

Laurila: Would you be pitching in Detroit had you not added the sinker?

Foley: “Honestly, probably not. It’s become an extremely effective pitch for me, whereas in the past I would throw four-seams at 98-99 [mph] and they would get turned around. And that was in High-A. I’d be like, ‘How does that happen?’ Now I know that my four just didn’t profile well. Throwing sinkers opened up a whole new style of pitching for me, and so far it’s been working well.”

David Laurila grew up in Michigan's Upper Peninsula and now writes about baseball from his home in Cambridge, Mass. He authored the Prospectus Q&A series at Baseball Prospectus from December 2006-May 2011 before being claimed off waivers by FanGraphs. He can be followed on Twitter @DavidLaurilaQA.

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1 year ago

Former Mepham Pirate. Congrats Foley..