Michael Kopech Breakout?! Gallen's Changeup Issues
Michael Kopech, Matthew Boyd, Kodai Senga, Zac Gallen
I’ll be taking Memorial Day Weekend off for some travel. Be back with notes Tuesday! It’ll likely touch on most of what I missed.
White Sox Michael Kopech has dominated in his last 2 outings. Totally understandable to be skeptical here, but under the hood there’s more going on. The simple fact is that his velocity is up 1 mph on his four-seam, 2 mph on his slider. The more nuanced point is that when comparing yesterday’s start in particular to his prior 3 outings, his release point is down 3-4” from 5.8’ to 5.5’. This also coincides with his extension creeping up to 6.85’ from 6.67’ between 4/26 and 5/7. My guess is that there’s something going on mechanically here as this big of a release height drop doesn’t seem like the 1-2” seen in normal variance. Swing-miss on the fastball has jumped from 22% in late April / early May to 42% in his last two starts, contact quality much weaker (down 6 mph average exit velo). Interesting that FanGraphs Stuff+ model thinks the fastball is only marginally better 123 to 125. 📈
Along with the 2 mph of added slider velo, he’s also dropped a bit of sweep on the pitch, going from 6” to 3” in his last 2 starts. So it’s becoming more of a bullet rather than a short sweeper (this lines up with the pitch being thrown harder, hard to maintain spin-induced break up 2 mph). Swing-miss there has also jumped from 20% to 40%. FanGraphs Stuff+ goes from 100 to 111 on the slider, saying this change is more important. Is there a possibility this isn’t real? Sure, always exists. But with this info, I’m in on a rebound.
Tigers Matthew Boyd tweaked his slider. The pitch went from averaging -2” vertical break (drop) and 5” sweep at 79 mph to having 1” vertical break (lift) and only 3” sweep at 81 mph. Velocity probably driving both the vertical break increase and loss of sweep. This is maybe right on the line of normal slider variation, but he threw more sliders with positive vertical break yesterday than he had in his prior 5 starts. Could be as simple as just trying to throw it harder. 10 whiffs on 13 swings is pretty wild. FanGraphs Stuff+ bumped this from a 92 to a 108. Big change. Kudos to Nick Pollack of Pitcher List for catching this one. 🐅
Mets Kodai Senga’s sweeper usage has been down in the month of May. He used it 17% of the time in April, down to 10% in May, 9% yesterday. The pitch also had a lot more drop and was thrown harder yesterday. Up 2 mph with an added 3” of drop (you usually see the inverse, less drop = harder = behind the ball more). He’s a tough one to analyze because the splitter and sweeper shapes are so inconsistent, so there might be some normal variation when it looks like a deliberate change. FanGraphs Stuff+ thinks the sweeper is his best offering (111) despite the results (4 of his 6 HRs are off the pitch). It also thinks his cutter is his worst pitch (88), but that’s been his best non-splitter from a contact quality standpoint, even whiffs are limited. 👻
DBacks Zac Gallen has completely lost the swing-miss on his changeup in May. It generated 41% swing-miss at 17% usage in April and it’s down to just 7% swing-miss at 11% usage in May. Contact rate up from 59% to 93%. The shape looks really consistent, the only thing I see different is a 1 mph uptick in velocity. FanGraphs Stuff+ has downgraded the pitch from a 97 to a 74. Location either to righties or lefties is up in the zone slightly more but doesn’t appear material enough to cause this change. Perplexing one here. Striking to see that big of a swing-miss fall-off and that big of a contact rate jump. Is he tipping it? 🐍