Watching Yoshinobu Yamamoto pitch can be a surprisingly frustrating experience. The 26-year-old has a dazzling arsenal with immense upside, which he largely showed with a 3.00 ERA and a 28.5% strikeout rate last year. But with a $325M deal before throwing a major league pitch, there was an idea that Yamamoto is more than just a 3.00 ERA.
As 2025 lines up to be a healthy and full year for Yamamoto, there should be steps forward as he lives up to his contract. On the surface, there seems to be one clear way he can go from a good to a great pitcher: elevating his fastball.
Coming in at 95.5 mph from a low 5.5 ft. release height, Yamamoto can create exceptional attack angles in the upper third of the zone. His 1.5 degree height-adjusted VAA (HAVAA) ranks in the 95th percentile, suggesting he would see significant success from going up in the zone.
The pitch looks good upstairs, but it doesn’t get a strong whiff rate. While Yamamoto still utilizes the high fastball situationally, it’s not his primary target with his fastball.
Yamamoto’s fastball plot looks right in the center of the zone, but the location numbers are better than the plot appears.
He does a good job at keeping his fastball on the edges of the zone horizontally, while the data shows how significantly he keeps his fastball down.
Why doesn’t he go upstairs with the fastball and miss more bats? Simply put, he doesn’t need to. The lower fastball works better with his arsenal early in counts, and he still goes upstairs when necessary.
The Low Fastball Opens the Door for the Splitter
Yamamoto’s splitter is his number one pitch, and his low fastball usage helps its effectiveness. The splitter stands out with 90 mph velocity and a decent amount of drop for such high velocity. The pitch grades out at a 109 Stuff+, ranking ninth among splitters thrown by starting pitchers in 2024.
The only pitches similar to Yamamoto’s are from relievers Justin Martinez and Aroldis Chapman, and the only pitches with more drop and velocity are Jhoan Duran’s and Jose Soriano’s splitters.
Yamamoto locates his splitter down-and-armside to all hitters, doing an excellent job keeping it below the zone. The splitter has just a 24.8% zone rate, in the 11th percentile among splitters. Despite a low zone rate, the splitter gets swung at over 53% of the time. A lot of swings at a pitch out of the zone is precisely what Yamamoto wants, resulting in a high whiff rate and little damage.
The splitter doesn’t have the same efficacy if the fastball is up in the zone. Yamamoto’s splitter is a high velocity and average drop pitch, so it doesn’t have the time to fall off the table compared to a high fastball.
If Yamamoto primarily used a high fastball and low splitter combo, it would almost assuredly sacrifice splitter whiffs in exchange for better fastball production. Are fastball whiffs necessarily more valuable than splitter whiffs? They are not, and he doesn’t need to change locations to keep similar whiff numbers.
The Fastball’s Other Utility
Even though it’s a heatmap of a pitch that looks like it’d get destroyed, Yamamoto’s fastball succeeds in the strike zone and doesn’t entirely ignore the high section of the strike zone.
The 57.7% zone rate is in the 95th percentile, and the fastball returns a strong 38.2% ICR. Its low location keeps groundball rates up and prevents significant damage. Nothing special, but it gets the job done.
While Yamamoto turns to the splitter 40% of the time in two-strike counts, his fastball is the secondary pitch at 30% usage. In those counts, Yamamoto throws his fastball up around half the time. Although that’s still 12% lower than the league average, it’s a huge step up from the 29% HiLoc% in non-two-strike counts.
Flashing the high fastball on occasion also sets up the curveball. Yamamoto’s curveball is also a similarly high zone rate pitch, which succeeds the most by earning called strikes. It has an elite 29.4% called-strike rate while maintaining an above-average 13.8% swinging-strike rate, combining for a cumulative 43.2% CSW%.
Showing a high fastball that causes hitters to freeze up when they see a big loopy curveball. Since this isn’t his main secondary, there isn’t a need to increase the high fastball. The occasional usage is enough to keep hitters off balance for the curveball, and Yamamoto prefers to use the splitter off the fastball.
The 2025 Outlook
The low fastballs should be a plan that sticks around this year, and Yamamoto can create effectiveness without going to the desired high fastballs. The Dodgers’ pitching philosophy centers around lower fastballs, which is against the “conventional” wisdom for one of the most analytically focused teams in the sport. They were one of seven teams with less than 50% high fastballs from starters (as sorted by innings 1-5) in 2024.
Yamamoto’s projections look strong: a 3.40 ERA with a 26% strikeout rate is nothing to scoff at. With a fastball that prevents hard contact well and plays off of both his secondary pitches, Yamamoto also has a cutter, sinker, and slider in the bag. Their sub-5% usage is enough to keep hitters off his three primary pitches. I could see him repeating his 3.00 ERA, if not better: the low fastball keeps home runs down, and I could see Yamamoto coming closer to his 2.61 FIP than what the ERA suggests.