Casey Mize Looks Completely Different

The Tigers rookie has made arsenal changes across the board

Casey Mize’s career at Auburn was dominant. He finished with a 2.96 ERA and 324 Ks in 267.1 collegiate innings, and established himself as one of college baseball’s premier aces despite going undrafted out of high school. It all culminated with being selected by the Tigers first overall in the 2018 draft. Being taken 1.1 always comes with high expectations and although Mize was the consensus top pitcher in the draft, I found myself somewhat skeptical.

In addition to the injury history and herky-jerky mechanics, my main concern with Mize was his arsenal. Evaluators had lauded his “deep pitch mix” and to be fair, Mize does throw a lot of pitches. Armed with a 4-seam fastball, sinker, slider, curveball, and a devastating splitter, he has an abundance of options to work with. The issue was that a number of pitches tended to look the same. He had a repertoire that gave the allure of depth but was severely limited by the lack of diversity. His splitter is dominant and was arguably the best pitch in the draft, but the fastball and sinker were less impressive, the curveball was not thrown with regularity, and the slider was so flat that it often blended in with the fastballs. If we treat the slider like a cutter, Mize essentially becomes a pitcher who throws 4 types of fastball — and not much else.

Since turning pro, some of those concerns have come to the surface, along with an injury history that clouds his pedigree even further. Though still a consensus top prospect, Mize found himself surpassed in the Tigers’ pitching prospect hierarchy — with most evaluators preferring Matt Manning and Tarik Skubal over Mize if given the choice. The splitter was still a legit weapon, but the fastball shape and slider depth were not optimal for missing bats. Luckily, after more of the same in his major league debut last season, Mize comes into 2021 with some notable changes to his repertoire.




Prior to 2021, Mize’s high-80s slider was more of a “slutter” — resembling a cutter more than a traditional slider. Baseball Savant even classified it as such. Plenty of pitchers succeed with this firmer/flatter slider shape, but they are typically used to generate weak contact and are often accompanied by a more defined breaking pitch, something Mize was lacking.

Two starts into 2021, Mize’s slider looks noticeably different:

Mize’s 2020 version was really more of an inefficient cut fastball, especially given its velocity. It doesn’t take much to tweak a slider though, as large movement changes like this can be achieved by simply moving the tilt of the ball in the pitcher’s hand. Doing so can substantially alter the pitch’s spin direction, without affecting other features like velocity. In 2021 he has added over 3 inches of downward vertical break to his slider, and that certainly helps its bat-missing ability. Here is a comparison of his arsenal, with 2020 on the left and 2021 on the right. Note: Mize’s slider was classified as a cutter in 2020, but I am fairly certain they are the same pitch.

As you can see, Mize’s slider has gone from a spin direction of 12:15 (similar to that of a typical 4-seam fastball) in 2020 to 10:15 in 2021. This change does absolute wonders for his pitch mix. It’s not just about simply adding movement, it’s about adding effective movement that fits in your arsenal.

Mize’s new slider finally gives him a distinct breaking ball with glove-side movement, and looks like something that will be a usable whiff generator. Both Mize and his battery mate have noticed it, turning to it 25% of the time through two starts. “I might’ve fallen in love with his slider too much in his first outing,” said catcher Grayson Greiner, noting that he still considers the splitter to be Mize’s bread-and-butter and turned to it more often in his second start versus the Astros. The splitter and slider now give Mize a pair of distinct out-pitches and deepen an arsenal in an effective way.




In addition to the slider, Mize has also improved his 4-seam fastball shape. For 4-seam fastballs, 12:00 is the optimal axis for backspin — which is how pitchers like Gerrit Cole get that “rise” effect when thrown up in the strike zone. The closer a 4-seamer is to 12:00 spin axis, the more whiffs it should be able to generate.

Going back to Mize’s spin direction chart from above, you will notice his fastball spin direction has gone from around 1:30 in 2020 to 1:00 in 2021. As a result, Mize’s 2021 fastball shows both increased vertical movement and decreased horizontal movement. Like the slider adjustments, this tweak not only helps optimize whiffs but also separate his pitches into a more well-rounded arsenal.

Oh, he’s also sitting 94-96 now — up 3.1mph from his 2020 average. That will play.


The Tigers might be on to something


Though the command can still be spotty at times and the mechanics are still herky-jerky, these noticeable pitch mix changes should be beneficial for Casey Mize’s long-term outlook. While his 2021 sample is still a bit small, I’m cautiously optimistic that these tweaks will help Mize improve on his bottom-of-the-barrel whiff rate as the season progresses. More importantly though, the Tigers as an organization are making some notable pitching-related improvements. Mize is not the only Tigers pitcher who is showing developmental progress, and the vast majority appear to be conscious changes rather than simply natural progression. The Tigers already have an impressive group of talented pitching prospects and showing they can not only develop that talent but help make them better, bodes well for the future of their rebuild. With Mize, Manning, and Skubal atop their rotation, the Motor City future looks bright.


Photo by Cliff Welch/Icon Sportswire | Adapated By Aaron Polcare

Natan Cristol-Deman

Natan is a California native and senior at UMass Amherst. He enjoys applying analytics to scouting and player development. You can find him on twitter @natan_cd

Leave a Reply

Your email address will not be published. Required fields are marked *

Account / Login