How Yoshinobu Yamamoto mixed up his arsenal and became the breakout star the Dodgers desperately needed

Los Angeles Dodgers right-hander Yoshinobu Yamamoto didn’t allow a hit through his first six innings on Tuesday against the Arizona Diamondbacks. Though he eventually yielded a leadoff single to Ketel Marte in the seventh, he would go on to record his second start of the month in which he completed six or more innings and surrendered only one knock. Repeated dominance in short order helps explain why he’s sporting a 1.86 ERA after Tuesday’s game, the second-lowest mark among all qualifying National League pitchers (behind New York Mets right-hander Kodai Senga).

Were economic or ecological collapse to cause Major League Baseball’s season to end today, no one would care about trivialities such as the Cy Young Award. Shy of those worst-case scenarios, Yamamoto has built an intriguing candidacy through the first two months. (Or, at least, as intriguing of a candidacy as one can with so much season remaining on tap.) In addition to his 212 ERA+ and 3.78 strikeout-to-walk ratio, Baseball Reference estimates that he’s already tallied 1.8 Wins Above Replacement — the exact figure he posted last season, albeit in eight more outings.

Yamamoto has, then, performed at the level the Dodgers imagined he could — and would — when they guaranteed him $325 million before he had thrown a single MLB pitch. (Yamamoto has the second-best odds, +310, at FanDuel.) Just what is he doing differently this year versus last? Below, CBS Sports has identified a few key changes.

1. Arsenal tweaks add unpredictability

A recent school of thought in pitching strategy had hurlers streamlining their arsenals, trimming the excess and prioritizing their best offerings. Baseball is a game of cycles, however, and it seems that there’s now some semblance of movement back to broader repertoires. Yamamoto isn’t going full Seth Lugo, deploying up to 10 pitch types per game, but he’s beefed up his menu.

When Yamamoto came over from Japan, he was known for a riding fastball, devastating splitter, and high-spin curveball. He used that trio 88.1% of the time last season. So far this season, those three pitches have a usage rate closer to 83%. While that’s not the biggest shift, it has allowed him to carve out bigger roles for his sinker and cutter: they represented 8.8% of his pitches last season, as opposed to the 14.4% usage rate they’re combined for in 2025.

The overall usage rate belies that Yamamoto has taken to using the sinker and the cutter more than 22% of the time against right-handed batters. The individual pitch results have been mixed — his sinker has better topline stats, but his cutter has better ball-tracking data — yet it’s worth considering the potential downstream effects here, specifically as it relates to his other fastball.

Yamamoto’s four-seamer has performed better from a surface-level perspective. Could some of that be attributed to the interplay the four-seamer is experiencing with his fastball variants? Keep in mind, he’s good at spotting his four-seamer to either side of the plate, leaving batters (particularly those who hit righty) to concern themselves with a sinker bearing in or a cutter tailing away. Perhaps this is all just a combination of noise and small samples, but it stands to reason that there could be something to this effect, however difficult it is to quantify.

2. Sequencing changes equals better first-time results

There’s another cascading effect at play whenever a pitcher introduces or emphasizes more pitches: the impact it has on sequencing. That can mean within a single at-bat, but it can also mean in subsequent encounters between the pitcher and the hitter. Without getting too far in the weeds here, let’s focus on the second dynamic.

Whereas last season Yamamoto would throw his four-seamer 43.2% of the time in first encounters, 40.4% in second encounters, and 35.6% in third encounters, this year has seen those numbers shift to 39.9% in first, 33.6% in second, and 33.8% in third. In a sense, Yamamoto’s padded arsenal has allowed him to treat first encounters like he did second encounters, and second encounters like he did third encounters. Perhaps relatedly, he’s faring much better the first time through the order this season, with his OPS dropping from .791 to .469. (His marks are similar in the second and third encounters, something that wasn’t much of an issue last season anyway.)

Again, the cutter and sinker don’t necessarily have to be load-bearing pitches for Yamamoto in order to change the dynamic and frustrate hitters.

3. Form and function alter location

There’s one other notable way in which Yamamoto has changed: his location. Sort of, anyway. The exact shifts in his geography appear to be a function of the amplification of his cutter and sinker rather than an intentional, arsenal-wide shift. Think about it this way. Where would you expect him to throw his cutter? How about his sinker? If you answered “down and to the glove side” and “down and to the arm side,” then congratulations on being correct. Collect your prize at the door.

In turn, Yamamoto’s overall location rates suggest he’s landing his offerings down and away from batters more frequently.  You can compare his location on the rest of his arsenal if you’d like, but to these eyes he appears to be placing them in roughly the same areas, just with the added entanglement of those other offerings.

It’s impossible to pin down just how much Yamamoto’s sinker and cutter have meant to his performance this season, but it’s clear that he’s become a more difficult at-bat thanks to the added unpredictability and interplay at hand. That Yamamoto has evolved, and that he’s now excelling as the ace of a World Series threat, shouldn’t come as much of a surprise. This is what happens when you take an all-world talent, pair them with arguably the best player development machine in the sport’s history, and provide them with ample time to get everything just right.