Starting Pitcher Notes (May 17): Roki Sasaki's career outing, Zack Wheeler FOMO, and Lucas Giolito's 2026 debut
Corbin Young examines a few starting pitchers from May 17, including Roki Sasaki, Zack Wheeler, and Lucas Giolito.
There are reasons why I haven’t been as active on here, mainly because of additional content on RotoGraphs in addition to Yahoo Fantasy. I’ll link the articles from last week below.
Roki Sasaki, SP, Dodgers
Los Angeles Dodgers’ starting pitcher Roki Sasaki reached career highs in innings (7) and strikeouts (8) in an outing throughout his brief career. Sasaki had a 19.8% swinging-strike rate and a low 24% ball rate on Sunday against the Angels. For context, Sasaki had a 10.7% swinging-strike rate and 39% ball rate in his career before Sunday.
⏩Sasaki was pumping four-seamers in the zone 80% of the time on Sunday. The four-seam added 3 inches of arm-side run while generating strikes at a high rate after he threw the heater in the zone, 52.5% of the time in 2026, down from 63.6% (2025). He was probably fortunate to throw the four-seam in the zone that often on Sunday since the Angels were hitting them hard like the season-long results against righties (.598 wOBA, .547 xwOBA).
🛝Since Sasaki’s slider has been one of his best pitches against right-handed hitters (.182 wOBA, .125 xwOBA), it would make sense to throw it more often. He threw sliders 43% of the time to right-handed hitters on Sunday, compared to 24% in 2026. Sasaki’s slider elicited a 28% swinging-strike, as he located them low and away from right-handed hitters on Sunday.
🪓Sasaki’s splitter was thrown nearly 2 mph (-1.9) slower on Sunday, leading to 3 more inches of drop with the spin rate dropping by over 100 RPM (-140 RPM). He mostly peppered the splitter low and away from left-handed hitters, though some hitters chased low and below.
Sasaki’s Stuff+ (107) and command (104 Location+) have been much better over the past three outings before Sunday. I might regret the drop earlier in the season.
Zack Wheeler, SP, Phillies
Zack Wheeler was off my draft board, which has been looking pretty silly so far in 2026 after throwing 7 scoreless innings, with 4 hits, 1 walk, and 8 strikeouts against the Pirates on Sunday. Wheeler’s velocity was up over 1 mph on all his pitches on Sunday, inching closer to his 2025 numbers.
⏩Wheeler was pumping his four-seamers in the upper parts of the zone, leading to opposing hitters chasing them above the zone, given his 50% chase rate. After Wheeler threw his four-seamer in the zone 60-61% of the time, it dropped to 56% in 2026 before Sunday (40%). That coincides with hitters chasing the heater more often in 2026 (38.2%) after being around 26-27% over the past few seasons.
🪓Wheeler has been increasing the splitter usage to left-handed hitters, throwing it 16% on Sunday and 17.9% in 2026 before Sunday’s outing. For context, Wheeler’s splitter was thrown 10-11% of the time against lefties in previous seasons. Though Wheeler’s splitter elicited zero whiffs on Sunday, it had a 27.1% swinging-strike rate while generating weak contact against lefties (.180 wOBA, .231 xwOBA).
Wheeler’s stuff and command numbers have dropped, yet are somewhat similar to recent seasons and his career averages.
Lucas Giolito, SP, Padres
The San Diego Padres called up Lucas Giolito on Sunday against the Mariners, who had okay results, though his velocity was down 3 mph or more on 3 of 4 pitches. If we rounded up, Giolito’s velocity would’ve been down by 3 mph on each of his pitches on Sunday.
😬He outperformed his expected metrics last season, and his 2026 debut was underwhelming, given his 6.4% swinging-strike rate and 44% ball rate on Sunday. For context, Giolito had a 10.2% swinging-strike rate and 36% ball rate in 2025.
⏩Giolito’s four-seam had a middling 9.3% swinging-strike rate on Sunday. However, the heater was generating called strikes (33%) and first-pitch strikes (73%). Giolito was probably lucky with the four-seamer because it allowed a 5 hard hits (95+ mph exit velocity) and a 97.1 mph average exit velocity on Sunday.
Giolito’s stuff has been trending downward, so it’s hard to consider him as a streamer with some confidence.