Is Edwin Jackson Throwing a Cutter?

Don Cooper is one of the game’s best pitching coaches in part because of how quickly he can teach and encourage pitchers to use the cutter. Countless White Sox pitchers have become benefactors of the pitch, including John Danks, who has quickly morphed into one of the finest pitchers in the American League. It should be no surprise that the White Sox’s biggest trade deadline acquisition – Edwin Jackson – is already showing signs of possibly throwing a cutter despite still being fresh-faced to the team.

For those unaware, Jackson has made five starts for the Pale Hose. Racking up over seven innings per start (on average) and posting a 5.63 K/BB ratio. That’s more than double Jackson’s previous career best ratio. Now, it is only 36 innings, and lots can happen in such a small sample size. My statement is not just based on that success, but also the pitch data coming in from Jackson’s brief time in the Southside.

Baseball Info Solutions’ data has Jackson’s fastball moving from 94 MPH to 95.4 MPH, his curve gaining about a mile per hour, and his change doing the same. His slider, though, has not only increased in usage, but also jumped nearly 3 MPH. That didn’t quite feel right, so I went to the pitchfx data to see if there’s been any change in movement on the slider. Here’s what I found:

4/6-8/1: 21.8% usage, 85 MPH, 1.43 vertical movement, 1.24 horizontal moment, 20.8% whiff

8/4-9/1: 27.6% usage, 87.9 MPH, 2.75 vertical movement, 0.16 horizontal movement, 30.6% whiff

That’s not definitive or anything, however everything points to something. Whether it be a new grip or arm slot or just random coincidence, I don’t know for sure. Admittedly some of this an inherent bias thinking that Cooper would quickly latch onto Jackson and morph his arsenal a bit with the addition of a cutter, but the data seems to support that a bit. We’ll see how it works out and whether Jackson will be the newest member of the Don Cooper fan club.

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I’d be curious to know who the top 5 best and worst pitching coaches in baseball are by the numbers. But that’d take a TON of work.


How would you do it? I guess you could look at individual pitcher’s FIPs under various coaches but the numbers would be small. How long is the average pitching coach in his job and how many chances does he get with new guys in that time? I think those are small numbers. Then there is background noise. Pick up a guy who is 26 and on the rise vs one who is 34 and about to decline. Guys who come back from injuries, who reach free agency coming off a career year, are nentendered after a bad year or are moved to the bullpen all add noise to hide the signal. You wouldn’t get any knowledge about what kind of an effect he has on guys who come up through the minors or are traded from another organization and immediately placed on the big league club. I think it would be a great idea I just don’t know that you could do it objectively.