Jenrry Mejia has had a rough time in the Arizona Fall League. Wednesday, he was clocked over 97 mph with his fastball and sat 94-96 mph, but was still hit up for five runs.
The colors follow Gameday’s pitch identification algorithm. I think it’s fairly clear that Gameday is miscategorizing some of Mejia’s changeups as two-seamers. In fact, all of the pitches that Gameday thinks are two-seamers, I think are changeups. The blue circle are the pitches I think are changeups.
In Mejia’s previous start, he did throw a lot of two seamers in the 93 mph range. I’ve circled what appears to be a cluster of fastballs that could be two seamers although their velocity matches Mejia’s other four-seamers. One thing the chart makes clear is both the incredible movement on Mejia’s heater, and it’s variability. Mejia simply must learn to harness his ability to make the ball move, but do so in a way where he can control it. He’s not doing that now.
Lets focus in on the movement on Mejia’s offerings. The graph below shows both the horizontal and vertical movement on each of Mejia’s pitches. Outside of the two curveballs he threw, the striking thing about the chart to me is that everything else is fairly indistinct.
The take home message for me: there’s a lot of velocity (duh!), but everything else needs some work.
in mejia’s defense, he’s only giving up singles. i bet his BABIP is astronomical right now.
Mejia’s stats have been pretty wacky.
14.1 IP
25 H
0 HR
13 BB
16 K
21-6 GO-AO
.481 BABIP
His control obviously hasn’t been good, but that BABIp really is grotesque
It’s fine for the 2-seamers (the real ones in the green circle) and the changeups to have the same movement. Pitch f/x research (I think it was Josh Kalk or Dave Allen) has shown that 2-seamers or fastballs that tail are more effective vs. same-handed batters, while obviously changeups are much more effective vs. opposite-handed batters. Once Mejia is past the developmental stage he probably shouldn’t mix and match those 2 pitches within the same at-bat. At least not too often anyway.
The fastballs are more of a continium than 2 or 3 distinct pitches and yeah that’s not really what you want ideally. Do you know if he deliberately throws a cutter in addition to his 4-seam and 2-seam? It almost looks like 3 groups of fastballs but it’s hard to tell.
You’re right to point out that Mejia doesn’t repeat his movement the way a fully developed ML pitcher does but at the extremes, he has the differentiation in movement to be really really successful.
The really unique thing about Mejia is the 4-seam. That kind of velocity is rare but rarer still to be accompanied with so much “sink”. Which is why it doesn’t stand out (movement-wise) from his 2-seam and changeup as much as some other pitchers.