Analyzing The Potential Of Casey Mize

Nick Pollack begins his Going Deep pledge with Casey Mize.

With the MLB officially missing games in 2022, I have pledged to write a Going Deep article every day until the lockout is lifted. Please consider supporting Pitcher List with a PL+ subscription to help us survive through these difficult months.


Here’s the deal. MLB officially canceled games of the 2022 season, and we don’t have an understanding of when we’ll see our favorite sport back in action. I, in a state of defiance and reluctance to let go of this game we all adore, elected to use this extra time to make a silly pledge that I’d write a Going Deep article every day until the lockout is lifted. So here we are talking about … Casey Mize.

Why not Casey Mize? Well, I’m not sure there’s a whole lot to talk about. Matt Wallach and Natan Cristol-Deman each outlined dramatic shifts in Mize’s approach last year, and as a man who is more excited to watch a Justin Dunn start than an episode of Euphoria, I’m somehow passive about the former #1 overall pick from Auburn entering 2022.

But don’t worry. Pitching is rooted in giving humans the task of throwing a ball into an imaginary box, and somehow each individual finds a different way to do it, exposing their character through flailing appendages and mental warfare. Mize is no exception.




When I first saw Mize in 2020, he showcased a pedestrian set of skills (check out the GIF Breakdown I wrote of his MLB Debut). His four-seamers and sinker sat 93/94 mph, a hard 88 mph slider/cutter was able to sneak around the edges, his splitter threatened whiffs but was wildly inconsistent (shocking, I know), and his curveball was…serviceable. Not the most lavish review, I know.

Good news for us, Mize was a bit different in 2021 than his brief six starts in his first year, but I’m not sure it was enough. As I’ll do constantly in these articles, we’re going to start with a discussion about fastballs.


The Not-So-Incredibly-Fast Balls


Indulge me for a moment to talk about not just Mize’s heaters, but fastballs in general from prospects. Unless we’re seeing dramatic results from a heater, I generally don’t get excited about fastballs from young arms unless they come in at 95+. Great exceptions include Joe Ryan and Alek Manoahbut these are just that: exceptions. Mize features a four-seamer and sinker each sitting around 93-94 mph and they are … Well, they are. 

I was going to make a table, but there isn’t much to tell. His four-seamer shows a touch of promise with an 11% SwStr rate and intent to elevate in 2021 and is slightly above-average at limiting hard contact, but it’s far from the foundational heater that his secondaries amplify.

Mize’s sinker failed to do its most important task: keep balls in the yard. He allowed ten longballs on the pitch last year off a 25% HR/FB rate. He elected to feature the pitch more often against right-handers, boasting a 36% O-Swing as he tossed the pitch inside 60% of the time. It helped him escape a few jams like this one against the Angels:


In short, Mize’s heaters aren’t a spectacle. He’ll need another weapon inside his repertoire to propel a transformation in 2022.


The #2 Pitch


Back in March 2021, I was hoping to see a shift. Where? Didn’t matter, just something to catch our eye and demonstrate adaptation and development. In what may be the best news of this article, Mize did, in fact, evolve.


Casey Mize’s Slider Change

loLoc% = Low Location%. hiLoc% = High Location %.


That is Mize’s slider growth in 2021 and it’s a whole new pitch. So much so, Savant classified 2020’s version as a cutter and the recent adaptation a slider. It came in slower, stole strikes more often, and shifted from nipping the top of the zone to inducing grounders at the bottom of the zone. And as you’d expect from a significant velocity drop, it came with a different shape.

Here’s its 2020 iteration:




And the new 2021 slider:



There’s Mize’s #2 offering and I’m fine with it. It doesn’t come with major whiff potential, and it works more as a solid strike offering Mize can toss at any time. But it does make you wonder, if this is Mize’s second pitch, is there a way for him to get whiffs?


I Was Promised Whiffs


Rounding out Mize’s repertoire are a splitter and curveball and I’m not sure if you recall, but that splitty generated a good amount of hype when he made his debut. How could this pitch not?



What a tease. That pitch earned a 32% SwStr game as it went 6/19 whiffs on the night and we were thrilled! Ecstatic! Our eyes were filled with wonder and hope, envisioning the years of Mize as a fastball/slider control arm with a wicked spitter that can fall off the table.

His debut returned seven strikeouts in four frames and here we are now, 36 starts later, with just three games of seven strikeouts in Mize’s career. Three, including that debut.

We could yell at the splitter for the sub 20% strikeout rate last year, though there is something interesting going on with the tumbler:


Casey Mize’s Splitter LHB/RHB Splits

The common convention is to throw pitches that fade away from batters. The right-handed Mize would throw a changeup/splitter more to left-handers since it fades away from the barrel and into the opposite batter’s box. Mize tried that and it clearly failed. That’s an abysmal SwStr rate as the pitch did a horrific job at earning strikes, forcing Mize to rely too heavily on fastball/slider against lefties. This is a glaring problem.

However, I can’t help but get intrigued by its debilitation of right-handers. A 70% strike rate and 47% O-Swing is phenomenal and I’m curious if those results can survive if he bumps up their RHB usage above 15%. Something to watch in the year ahead.

There is one more pitch in the arsenal and let’s talk about that quickly.


Oh Right, Mize Has A Curveball


I wouldn’t expect a whole lot of hope in Mize’s curveball. When it comes to hooks, there are two camps: A golden pitch that acts as the signature weapon of an arsenal (think Charlie Morton, Rich Hill, Adam Wainwright), or it’s a show-me pitch with low usage that aims to steal called strikes (Max Scherzer, Patrick Sandoval, Eric Lauer). Mize’s yacker falls into the latter category, though we normally want to see 20-25% called strike rates for us to feel confident in its ability.

Mize’s curveball carried an 18% called-strike rate with a mediocre 57% strike rate. Not great.

I wouldn’t expect this pitch to be the savior of his arsenal any time soon.




There are a few elements I skipped over that I want to hit quickly. Mize is in a great situation this year with what seems to be full freedom to pitch every five days in Detroit as he averaged about 85 pitches per start before his September shutdown—and that includes his July slowdown. It’ll give him time to potentially take a step forward as he continues to get experience on the bump.

With an improved defense behind him (and maybe another infielder is on the way?) Mize could see his questionable .254 BABIP stay above average for another season, albeit not that low. It could pave the path for another solid season, though the final point of consideration is Mize’s dramatic spin rate drops (about 100-200 rpm on his four-seamer) post sticky-stuff ban. It didn’t seem to affect him a whole lot, but hey, it’s something to think about.

Here we are, the end. Mize has a touch more intrigue than I anticipated with his splitter performing better than expected against right-handers and could open the door to a push over the 20% strikeout hump. Still, I’m not anticipating a major shift in fastball and slider ability, and it could spell for an MLB-friendly season that doesn’t do a whole lot for your standard fantasy team.


Photo by Cliff Welch/Icon Sportswire | Adapted by Justin Paradis (@JustParaDesigns on Twitter)

Nick Pollack

Founder of Pitcher List. Creator of CSW, The List, and SP Roundup. Worked with MSG, FanGraphs, CBS Sports, and Washington Post. Former college pitcher, travel coach, pitching coach, and Brandeis alum. Wants every pitcher to be dope.

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