A version of this story originally ran on March 5 after Sasaki's Spring Training debut.
The Roki Sasaki splitter is here. And it's about to take center stage in Tokyo.
Sasaki's splitter was the star of the show in his two Spring Training outings for the Dodgers. It has the potential to be one of the best pitches in baseball. So when the 23-year-old phenom makes his hugely hyped MLB debut on Wednesday against the Cubs in the Tokyo Series, all eyes will be on the split.
Tokyo Series 2025: Dodgers vs. Cubs
? Ohtani ignites Dodgers past Cubs in Tokyo Series opener
? Top moments from Tokyo Series Game 1
? Imanaga bests Ohtani in 'made for TV' Tokyo matchup
? Game 2 FAQ: Lineups, starting pitchers, how to watch and more
? 'I'll remember everything': Shaw makes much-anticipated debut
? Pok谷mon front and center as Tokyo Series celebrates Japanese icons
? Freeman (left rib discomfort) scratched from Tokyo Series opener
? MLB's history of games played abroad
? 150 years of history has led to historic Opening Day
? Seiya taking BP with a samurai sword is exactly as cool as it sounds
We already knew the Dodgers were cornering the market on splitters -- between Sasaki, Opening Day starter Yoshinobu Yamamoto and the soon-to-return-to-the-mound Shohei Ohtani, Los Angeles might have the three best splitters in the world.
But the splitter that Sasaki showcased this spring was unique.
And it was basically unhittable. Opposing hitters whiffed on 10 of their 12 swings against Sasaki's splitter -- an insane 83% whiff rate. Six of the nine plate appearances decided by his splitter were strikeouts.
So, Sasaki's splitter is filthy. Really filthy. And the Statcast data shows why.
Here are the three qualities that stand out the most about Sasaki's splitter entering his first regular season start for the Dodgers.
1) It has extremely low spin
Splitters are a low-spin pitch type. That's what gives them their "tumbling" movement that makes hitters swing over the top of the ball. But Sasaki's splitter is very low-spin.
The Major League average splitter spin rate was 1,302 rpm last season. Sasaki's splitter spin rate in Spring Training was 540 rpm. His six splitter K's came in at 584 rpm, 576 rpm, 570 rpm, 542 rpm, 520 rpm and 403 rpm.
That's almost like a knuckleball. Sasaki is throwing an extreme spin-killing splitter.
In the Statcast era, which goes back to 2015, there are 341 pitchers who've thrown at least 100 splitters (or forkballs) in a season. Sasaki's spin rate would be the lowest of them all.
Lowest splitter spin rate in a single season, Statcast era
Min. 100 splitters thrown in the season
- Emmanuel Ramirez, 2024 -- 550 rpm
- Logan Gilbert, 2024 -- 640 rpm
- Tylor Megill, 2024 -- 702 rpm
- Mark Leiter Jr., 2024 -- 769 rpm
- Mike Pelfrey, 2015 -- 784 rpm
- Aroldis Chapman, 2021 -- 787 rpm
- George Kirby, 2023 -- 799 rpm
Sasaki: Averaged 540 rpm on his splitter in Spring Training 2025
Maybe the most intriguing part about this is that it's something of a new look for Sasaki's splitter compared to what he showed in the 2023 World Baseball Classic.
In the WBC, his splitter was more of a true power splitter, averaging 91 mph and around 1,100 rpm. With the Dodgers, Sasaki's splitter is sitting at a lower velocity, around 85 mph, but with much more spin killed.
In that respect, Sasaki's splitter more resembled the spin killers currently deployed by the Mariners' star trio of Logan Gilbert (640 rpm), Bryce Miller (912 rpm) and George Kirby (946 rpm) than the power splitters thrown by his own teammates Yamamoto (90 mph / 1,326 rpm) and Ohtani (89 mph / 1,287 rpm in his last pitching season, 2023).
But Sasaki's splitter right now is even lower-spin than the Mariners trio. At its current spin rate, it would be the lowest-spin splitter in the Major Leagues today. The only pitch in 2024 with a lower spin than Sasaki's splitter was Matt Waldron's knuckleball.
2) The drop is ridiculous
There are two results of Sasaki's extremely low spin. One is that Sasaki's splitter extremely drops off the table.
That means Sasaki can either drop the splitter into the strike zone unexpectedly -- three of his six splitter K's this spring were strikeouts looking -- or induce chases on splitters that start in the zone but quickly fall out of it. All 10 of the swings-and-misses against his splitter in Spring Training were down and out of the strike zone.
Statcast has two ways to measure vertical pitch movement:
- The total amount the pitch drops from the pitcher's hand to the plate, which includes the effect of gravity pulling down the ball. And
- "Induced vertical break," which removes gravity from the equation and measures how much rise or drop the pitcher generates himself from how he throws the pitch.
Sasaki's splitter is top-of-the-class no matter which way you measure it.
In terms of total vertical movement: Sasaki averaged 43 inches of drop on his splitter this spring. That is a ton of drop for a splitter. In fact, it's more drop than any splitter in the Major Leagues had last season -- Astros reliever Tayler Scott and the Mets' Tylor Megill with his "American spork" had the most at 41 inches.
In terms of induced vertical break: Sasaki generated five inches of downward movement on his splitters. Again, that's a ton, especially for a pitch at Sasaki's splitter's velocity. As with his total drop, Sasaki's splitter IVB would have been the most in the Major Leagues last year. Scott had the most downward induced vertical break among splitters at four inches, followed by the Red Sox's Tanner Houck at three inches.
So Sasaki's splitter movement is already elite. And we've only talked about half of it.
3) It can break in both directions
This is the other half: Sasaki's horizontal movement. And it gets very interesting.
Almost all offspeed pitches -- splitters, forkballs, changeups, screwballs -- fade to the pitcher's arm side. But Sasaki's splitter moves in both directions.
A lot of his splitters run to his arm-side. But sometimes his splitter cuts to his glove side.
Here's a chart of Sasaki's splitter movement in his two Spring Training outings:
That's a very wide range of splitter movement from side to side. The running splitters move like his fastball, but with a ton more drop. The cutting splitters look almost like his slider ＃ only they come in harder and with less sweep. And all three pitches come out of the same release point.
The split in Sasaki's splitter movement direction this spring was close to 50-50. About half of Sasaki's splitters had running movement. The other half had cutting movement.
Sasaki got as much as nine inches of arm-side run on his splitter. He also got as much as eight inches of glove-side cut. That's a range of movement of 17 inches on his splitter -- the full width of home plate. In other words, if a Sasaki splitter starts off right down the middle, it might end up on either the inside corner or the outside corner of the plate.
"He throws it hard. It looks like a fastball," Dodgers manager Dave Roberts said of Sasaki's splitter after his Spring Training debut. "Some break straight down, some go to the left. Some go to the right. It＊s tough to square it up, because you just don＊t know what it＊s going to do."
It is very rare for a pitch to be able to do what Sasaki's splitter does. The possibility of his splitter breaking in either direction makes it unpredictable -- which is a trait of the pitch that Sasaki flashed in the World Baseball Classic, too.
The Roki Sasaki splitter looked like one of the nastiest pitches on the planet back then, and as he begins his Major League career with L.A., it still looks like that. It looks like MLB's next great pitch.