Q&A: Jack Leathersich, New York Mets Pitching Prospect

Jack Leathersich misses a lot of bats. If he can do a better job not missing the strike zone, he could have a bright future in the New York Mets bullpen. The 23-year-old lefthander has an eye-popping 15.2 K/9 in 143 professional innings. He also has averaged five walks for every nine innings pitched.

A fifth-round pick in 2011 out of the University of Massachusetts-Lowell, Leathersich split last season between Double-A Binghamton and Triple-A Las Vegas. He dominated Eastern League hitters, but his command issues flared up after his promotion. His numbers in Sin City included 47 strikeouts in 29 innings, but also 29 walks.

Leathersich talked about the need to fine-tune his command — and his strikeout-inducing arsenal — earlier this month.


Leathersich on mechanics and command: “The guys you play against at the higher levels are much better hitters and much more patient. I’ve learned that you need to command the strike zone. That’s what I struggled with in Triple-A this past year. The hitters have a better sense of the strike zone and aren’t swinging at borderline pitches, so you need to command your pitches and get ahead.

“I’m working on fine-tuning my mechanics. I’ve always thrown high in the strike zone, and I’m working on throwing the ball down and then climbing up the ladder when I need to. I’m not worried about my mechanics. I’m just working on them and trying to become more consistent.

“[The issue] has always been flying open. I need to keep my front shoulder closed, have a consistent stride and a consistent landing point. I do [have a max-effort delivery], yes.”

On his role and his repertoire: “My first year in Brooklyn, I was a piggyback — I was a starter but only threw an inning or two because I had thrown so many innings in college. The next year, I showed up to spring training as a starter, and they realized I was a lot more effective for one or two innings out of the bullpen.

“In Brooklyn, I was just fastball-slider. I started working on a changeup last year, but didn’t really throw it very often. This year, I started throwing it a lot at the end of the season. It’s a really effective pitch, and a fun pitch to throw, because it looks just like a fastball. That was my biggest thing this year. I worked on my changeup, and it was pretty good by the end of the year.”

On his changeup; “It’s like a two-seam fosh. I put my middle finger and index finger on the seams in a circle-type grip. I went through about 10 different grips before I found this one. I like it.

“My changeup velocity is around 85-86. My fastball is low-to-mid 90s, and a four-seam. I don‘t throw a two. Everybody said I should throw a four-seam changeup because I throw a four-seam fastball, but I couldn’t control a four-seam changeup for some reason. I switched to a two-seam, and it works for me.”

On his slider: “My slider is definitely my second best pitch, but I still need to work on it this off-season. I have to be able to throw it for a strike whenever I need it.

“It was a curveball in college and in my first year of pro-ball. but it progressively got harder, and now it’s a slider. You can call it a slurve, maybe. It’s definitely not a curveball anymore.”

On pitching to contact and missing bats: “A big philosophy [in the Mets organization] is to get ahead of the hitters. I want to try to get hitters out in three pitches or less. I’ve always thrown a lot of pitches, because I normally go deep in the count. That’s something I want to work on next year, getting more ground outs and fly outs.

“It’s funny, I’ve never really tried to strike batters out. That’s always just been the way I’ve pitched. But it takes a toll on you. You get tired when you throw a bunch of pitches each time you’re out there, so it’s a relief to get a 10-pitch inning. It all comes down to fastball command and getting ahead of hitters. I think I have a pretty good chance of getting them out if I get ahead.”

On his high walk rate: “It’s not like I’m trying to walk batters. I’ve always walked a decent number, and I need to eliminate those walks. But I’m not going to think about the past, because it means nothing. I’m just trying to work my way up. This off-season is huge for me to fine-tune my stuff and get on a better path. Fastball command has been my biggest issue and that’s what I’m going to work on this off-season.

“I’m happy with my career so far. I’ve been on winning teams every year, which has been a blast. I just need to keep working hard to develop my command. Hopefully it will pay off.”

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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Christian Migliorese
10 years ago

He could be a great lefty out of the pen.

J Katz
10 years ago

He’s exhibited reverse platoon splits in the minors though so I hope Terry Collins doesn’t get it in his head that he’s going to be a lefty specialist.

10 years ago
Reply to  J Katz

I’d be willing to bet he will. Collins is obsessed with handedness matchups, as was Manuel, and has historically ignored abnormal platoon splits both on his team and opposing teams.