A Fix for Walker Buehler. Brayan Bello's New Sinker Location

Walker Buehler, Brayan Bello, Spencer Arrighetti

• Dodgers Walker Buehler is struggling this season despite a serviceable outing last night. The issue is that his four-seam hasn’t been good in a while. It has a 7% swinging-strike rate with a .750+ xSLG this season. It makes me wonder whether he should only be throwing sinker-cutter to righties. His cutter is his only average fastball per FanGraphs Stuff+ (103) and his sinker is his best-commanded pitch by Location+ (106). I don’t think there’s a need to elevate against righties with the four-seam. Occasional elevation is fine, but 23% usage is too high for the results he’s getting. Versus lefties, the cutter should overtake his four-seam in terms of usage. His current distribution is 32% four-seam with 24% cutter. It’s fine to cut the four-seam usage in half and give most of it to the cutter. If he keeps the four-seam to lefties, at least alter the location. He’s throwing it middle-up right now and it’s overlapping 1:1 with where we expect damage (see heatmaps below). 🎬

  • Odd situation from my perspective. This feels like one of those spots where the Dodgers quickly make usage changes because of clear flaws, even if in this case, it might mean more walks. We haven’t seen that (yet). At this point, however, what do you have to lose with a guy holding a 5.50+ ERA and FIP in 10+ starts? He’s not startable in the postseason right now. The Dodgers goal is likely to find a way to change that. I think it’s through less four-seam.

Walker Buehler’s four-seam location and damage to lefties (2024). Notice how the red is in the same spot on both heatmaps. That is not good. It means you’re throwing the pitch where damage is occurring.

• Red Sox Brayan Bello started throwing his sinker primarily backdoor to right-handed hitters (see heatmap below). This has led to a 2.49 ERA and a 3.38 FIP in his last 4 starts, one of his best multi-start runs of the season. The sinker adjustment hasn’t changed the pitch’s results much, but it changed the contact quality allowed on his slider, which has pushed from a 34% in June-July to and 85%(!!) ground-ball rate in August. Given his slider is in the exact same location down-away from righties and there’s minimal usage change in his mix, it’s safe to assume that how hitters perceive the slider with his sinker sitting away instead of down is causing some visual issues. 🎯

Brayan Bello’s sinker location to righties (June-July vs August). Notice how on the left heatmap, his primary sinker location is further away from the hitter compared to the left heatmap.

• Astros Spencer Arrighetti has dominated in August (1.95 ERA with a 2.18 FIP). I mentioned in early August he was throwing more four-seam down-away to righties in early-count situations (link). That was unfortunately a blip. He instead elevated his four-seam in August to righties (see heatmaps below). The pitch’s swinging-strike rate went from 5% to 13%, and he took 150 points off the xwOBA. The more impressive adjustment is that he pushed his swinging-strike rate versus lefties from 12% to 18%. There isn’t an obvious usage or location change present. If you dig deeper into non-two-strike usage, there’s an increase in cutter usage from 14% to 24% when comparing July to August. The result has been more miss on almost everything in his mix to lefties (changeup, sweeper, curveball). 🤠

  • I don’t know if I buy Arrighetti’s hot streak. He has a 5+ FIP versus righties in August and his true domination is coming against lefty hitters without a clear reason why the swinging strikes have jumped. The extension is big (7’), the release is super low (5.1’) and he has average velo on the fastball (94.5 mph), but the net from FanGraphs Stuff+ is still below average (95). It sees the curveball and sweeper as plus and not much else. I see him as a ~4.30 ERA guy with above-average swing miss and otherwise average peripherals. If you believe in him long-term, you’re betting the release traits trump the raw velo/shape combination on the four-seam, and therefore Stuff+ is missing something. I’d be curious to know what I might be missing otherwise in his mix to project him more aggressively.

Spencer Arrighetti’s four-seam location to righties (July vs August). Notice how there are more pitches up-in to righties (red concentration) on the right heatmap compared to the left heatmap.