Jack Leathersich: The Human Pitching Machine

I like to watch movies with a twist—something unexpected that blows me away and leaves me wondering what the hell happened. That’s why I liked Memento, 10 Cloverfield Lane, and The Usual Suspects. Originality is in low supply out there, and a good surprise is always appreciated.

When the Cubs claimed lefty-reliever Jack Leathersich from the Mets in November of last year, the plot was pretty clear from the get go. Here’s a guy that struggles with his command,  strikes out everyone, and had just undergone Tommy John surgery.

The numbers tell the story pretty clearly:

Year Age Lev ERA IP BB/9 K/9
2011 20 A- 0.71 12.2 2.1 18.5
2012 21 A+-A 3.00 72 4.0 14.1
2013 22 AA-AAA 4.63 58.1 6.9 15.7
2014 23 AA-AAA 3.31 54.1 4.6 15.4
2015 24 AAA 5.40 13.1 4.7 14.8
2015 24 MLB 2.31 11.2 5.4 10.8
2016 25 Rk-AA 2.38 11.1 3.2 15.1

Leathersich has struck out 39 percent of the batters he’s faced in the minor leagues over his six-year career. If you’re like me, you saw those numbers and made a pretty obvious assumption: this guy must throw really hard.

It’s a good guess, but this piece is about plot twists, so here’s one: Leathersich “only” throws in the 91-93 range, despite reports that he could touch 95 earlier in his career. So what gives? How can someone with a good but not overpowering fastball strike so many batters out?

I figured there was something with his delivery that gives him a higher perceived velocity than what the radar guns are picking up. Statcast measures perceived velocity by measuring where the ball is released and how fast it appears to the hitter. If you’re not familiar with perceived velocity, just take a look at Carter Capps’ delivery: he has a good fastball, but his perceived velocity pushes him up to 101 mph because he’s jumping towards the hitter and releasing the ball so much closer to the plate.

I looked at all the pitches Leathersich threw in the big leagues last year and found nothing—there’s nothing wonky about how close he releases the ball to the plate. His perceived velocity and the speed on the gun is pretty much the same.

Dead end.

The Devil is in the Delivery

While Leathersich isn’t jumping towards home plate to get an edge on his fastball, he does have some deception in his delivery. See if you can spot anything out of the ordinary:

To my untrained, not-a-scout eyes, everything looked pretty normal. Then I started reading what others had to say about Leathersich, and it became clear I was missing something.

From this WSJ piece:

“He’s got to hide the ball. It’s got to be something,” said Ken Harring, Leathersich’s college coach at UMass Lowell. “In the spring, our guys would say, ‘We can’t pick the ball up.’”

What Leathersich lacks in raw stuff he makes up in funkiness. Mets catcher Kevin Plawecki, who worked with Leathersich in the minors, said Leathersich has an unconventional delivery and a deceptive arm angle. That coupled with his small frame—he stands 5 feet 11—makes his ball look faster than it is actually going.

“It’s definitely a hard ball coming in,” Plawecki said. “It kind of has that extra life to it, that extra zip to it. I don’t know exactly.”

Here’s what current Major League pitcher Zack Wheeler had to say about Leathersich: “Hitters tell me he throws an invisi-ball. For some reason, they just don’t see it very well.”

So I went back to poring over video of his delivery, and finally found one angle from behind home plate that seemed to capture some of that funk:

He appears to hold on to the ball until the very last minute, and then the arm quickly whips through to deliver the ball at a ¾ to sidearm angle. From the batter’s point of view, it’s tough to pick the ball up until it’s suddenly on top of you.

When I look at Leathersich, I’m reminded of why I always hated hitting against pitching machines: it was so hard for me to know exactly when the ball was going to get to me. I could never get the timing right consistently, whereas with a pitcher you see the windup and have a much better idea of when the ball is coming. Leathersich pitches more like a machine than your average pitcher…other than the lack of control.

Which is terrifying.

In that Leathersich video, check out the sequence around the 1:00 mark where the hitters are flinching to get out of the way. Yes, part of it is that the ball is coming right at them, but part of it is that they’re having trouble picking the ball up until it’s bearing down on them.

Leathersich’s funky delivery gives him an edge—and that’s why he’s so effective at striking batters out. His control, however, needs to improve if he expects to have a meaningful career in the big leagues.

Wild, Wild West

As you saw at the top of this piece, Leathersich walks too many hitters. Some players have good enough stuff that they accept the walks as part of who they are (Carlos Marmol, anyone?), while others actively try to improve their control.

Leathersich appears to be in the latter group, which is a good sign.

He’s already made a couple of adjustments to help bring those walk numbers down. First off, he was open to advice from more experienced teammates on dealing with control issues:

Leathersich spent around two hours talking with injured reliever Bobby Parnell, the Mets’ former closer. Parnell told Leathersich about his own battles with poor command from earlier in his career and how he overcame them.

The message was focus. Now, every time Leather picks up a ball, even while just playing catch, he pours all his energy into hitting his target. Since then, Leathersich said, everything’s “been going pretty well.”

That was before the 2014 season, and later on he also mentioned he was making other tweaks to his approach:

“I’m taking a different angle this year, embracing the process,” he continued. “It’s hard not to look at stats, but I haven’t done it once this year. I realized being in big league camp how older guys approach the game, and also how it’s about throwing strikes. That’s the name of the game. You don’t see guys in the big leagues walking guys, and if they do they’re not around very long.”

More specifically, Leathersich figured out that he needed to change one specific part of his approach to get more experienced hitters out. In his own words:

“Even though I was still getting swings and misses,” Leathersich said on Sunday, “I was also losing guys (to walks) or getting behind. And when you get behind on guys at that level, they make you pay.

“That stuff had never really affected me before, but at that level I realized I needed to make a change, so all offseason I worked on getting the ball down. I’ve made a couple of tweaks in my delivery to keep my front shoulder from flying open, and it should help me throw more strikes.”

The numbers from 2013 to 2014 an improvement without sacrificing the elevated strikeout rate:

Year Age Lev ERA IP BB/9 K/9
2013 22 AA-AAA 4.63 58.1 6.9 15.7
2014 23 AA-AAA 3.31 54.1 4.6 15.4

This willingness to adjust is a great sign of a player that’s willing to put in the time and work to stray from what has been successful in the past to become even better in the long run. Not all players are willing to deviate from “what got them here.”

Since becoming a Cub this year, Leathersich is working on coming back from Tommy John surgery, and continuing to work on his control issues without sacrificing any of the funk that makes him so good. So far, so good. In 9 innings, he’s struck out 18 hitters (17.4/9IP) and walked only three. While it’s a small sample size, it’s an encouraging sign that Leathersich can still strike hitters out and is actively improving his command.

I don’t expect Leathersich to post a 15 K/9 rate in the big leagues, but if he somehow manages to strike out even 13 batters per nine innings on a consistent basis, he’ll join an elite list of relievers (minimum, 300 innings): Aroldis Chapman (15 K/9), Craig Kimbrel (14 K/9), and Kenley Jansen (13 K/9).

Of those, Leathersich would be the only one who isn’t regularly hitting the upper 90s (or the 100s in Chapman’s case), and that would be a most pleasant twist in his narrative for Chicago Cubs fans.

Lead photo courtesy Mark J. Rebilas—USA Today Sports.

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1 comment on “Jack Leathersich: The Human Pitching Machine”

Ed Brown

His grandfather at 91 thinks he is doing just fine.

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