LOS ANGELES -- Before Roki Sasaki had thrown a pitch in the Major Leagues, those in the baseball world had already heard all about his splitter.
Sasaki's signature offering had the potential to be one of the nastiest pitches in the Majors, and indeed, it looked nearly unhittable at times in his rookie season. But due to issues with his fastball, he wasn't consistently able to play the splitter off the other pitches in his bag.
This year, Sasaki and his arsenal have continued to be in development. As it turns out, he was even willing to tinker with his signature pitch.
Sasaki showcased a revamped splitter that he leaned on more than any pitch in the Dodgers' 12-4 rout of the Cubs on Saturday evening at Dodger Stadium. The box score wasn't especially pretty after he gave up four runs, including three solo homers, but his stuff looked much improved as he pitched into the sixth inning for the first time this season.
"The first couple games, I couldn't go deeper. It was kind of frustrating," Sasaki said through interpreter Kensuke Okubo. "But right now, I'm just focused on what I can do, and then at the end of the season, I just want to be who I want to be."
It was also Sasaki's bobblehead night, leading reporters in the Cubs' clubhouse to jokingly ask Seiya Suzuki -- who had one of the homers off Sasaki -- if he would receive one for taking his former Samurai Japan teammate deep.
"I’m in shock right now, because I got a message from Shohei [Ohtani]," Suzuki said through interpreter Edwin Stanberry. "And he said Roki said that he doesn’t like me anymore."
Sasaki went to his splitter 48 times on Saturday. He has only thrown a higher percentage of splitters in a Major League start once, when they made up half of his pitch total on May 9 of last year. Usage aside, the splitter itself was different. He averaged 90.8 mph with it, up 5.8 mph from his season average. His average spin rate was 991 rpm, considerably higher than his season average of 574 rpm.
Sasaki said the splitter he threw Saturday is "pretty similar" to the one he previously threw while pitching in Japan. The metrics agree, as the splitter he threw during the 2023 World Baseball Classic averaged 91 mph and around 1,100 rpm.
“I think it’s more tunneled like the fastball," manager Dave Roberts said. "And you would think you’re gonna get more swing-and-miss. And today, with that split, it stays in the hitting zone a little bit longer and makes the hitter make the decision a little bit sooner.”
Sasaki missed bats with his harder splitter, generating a career-high nine whiffs with it. He was also able to drop it in for a first-pitch strike nine out of 10 times.
"It was in the zone, early in the count, and that alone is a little bit of a difference from the past," catcher Dalton Rushing said. "I think that's what allowed us to get some guys to chase a little bit later."
Dating back to when he signed with the Dodgers ahead of last season, Sasaki has often called himself a work in progress. Acknowledging that is one thing; being willing to make changes to his signature pitch in an effort to get better is another.
The Dodgers want to see Sasaki develop on the mound, but that mindset is another key area of growth in his sophomore season.
"To do that in the middle of a season, and change the profile of a certain pitch which has been your bread-and-butter pitch," Roberts said, "is a lot of trust and growth for Roki.”