I just dropped a new YouTube video (LINK) that introduces a pair of pitching concepts that could save starting pitchers: decay and buyback. In short, let’s start thinking about intra-game batter-versus-pitcher matchups more objectively.
Tigers Reese Olson is in the midst of an abysmal 3-start stretch: 14.2 IP, 28 H, 17 ER. I see a potential driver of the struggles—he started elevating his fastball more to left-handed hitters (see heatmaps below). I point this out because the xSLG on the pitch jumped from .357 in May to .576 in his last 3. It’s getting crushed in the zone by lefties. His fastball’s swing-miss to lefties has been cut in half as well. It’s a small sample, but in those last 3 starts, he’s been better versus right-handed hitters, where his slider and changeup are rolling (60%+ swing-miss on each). This makes the lefty struggles more apparent. 🐅
He is getting unlucky to lefties during this stretch from a batted-ball standpoint, but I’m curious why he started elevating his fastball. Intentional? Something mechanically different? Matchups? It seemed like he drifted more away in the zone in yesterday’s outing. We’ll see if that sticks. Given the shape of his fastball (more of a two-planer without any vertical or release differentiator), I think the location away makes much more sense.
Cubs Javier Assad started the year with a 1.49 ERA and a 2.93 FIP. In his last 5 outings, he’s reverted to a 5+ ERA and 5+ FIP. He’s leaning on his sinker versus right-handed hitters a lot more. The usage has increased from 46% to 59% while his cutter and slider are getting touched up in the zone (unclear why). The sinker is performing well but isn’t missing any bats. To lefties, his overall results have been fine. He’s running into some sinker issues despite jumping the pitch up about 9 percentage points in usage. His four-seam and cutter have been more concentrated on the inner third of the plate to lefties in these past 5 starts as well (you can see the four-seam location shift below). 🐻
I think he’s become far too predictable to right-handed hitters, especially with more middle-of-the-plate sinker locations. It’s unsustainable to throw one pitch near 60%, especially one that doesn’t miss bats. To lefties, I’m more optimistic given the depth of his mix and ability to flip-flop usage. I also like the general idea of pitching inside more with the four-seam and cutter. I don’t think the jig is up here. It feels like there’s something about his sinker that will allow him to pitch below his peripherals for an extended period of time. Aka, he can control ball-in-play more than most. We’re looking at a low 4s ERA guy, not a sub 3.