3 storylines to look forward to ahead of Roki Sasaki’s Dodgers spring training debut

The Dodgers' prized offseason addition is set to make his official-unofficial Dodgers and MLB debut on Tuesday night against the Reds. Dave Roberts confirmed that Roki Sasaki will appear in relief after a Yoshinobu Yamamoto start in his first Cactus League turn.

For all of the hype and heavy competition it took to get him, we still have yet to see Sasaki at full power (or, at least 80%, given that this is spring training). Ahead of his Dodgers debut, here are three storylines to watch out for.

3 storylines to look forward to ahead of Roki Sasaki’s Dodgers spring training debut

How will the splitter play against major league hitters?

A key piece of not only Sasaki's arsenal, but also Yamamoto's, Shohei Ohtani's, Shōta Imanaga's, and even Kenta Maeda's, is the splitter, which is widely taught and thrown in Japan. Sasaki's was on full display during the World Baseball Classic, and even earned a Pitching Ninja feature alongside his fastball — a 92 MPH splitter that behaves almost exactly like a 102 MPH fastball until it doesn't, when it dips away and well out of the strike zone.

Dodgers writer Blake Williams, in attendance at one of Sasaki's first live sim games, said the splitter was "as advertised," but we have yet to see it in competition. Even Maeda, who fell far from grace last year with the Tigers, still sees huge success with his splitter; if Sasaki's is even better than his, Ohtani's, Yamamoto's, and Imanaga's, then opposing hitters will have a huge problem.

What velocity will the fastball sit at?

Again, Sasaki can get into the triple digits and has on the big stage (the heater averaged 100.5 MPH in the WBC), but he posed a question to the final teams in his deliberations: Why did his fastball velocity dip in 2024, and how would the team help him fix it? The Dodgers must've had a good answer, seeing as he chose them, but he threw an average 96.8 MPH on it last year, down two MPH from 2023.

The Dodgers won't want Sasaki to blow out his arm in the very first spring training game of his MLB career, especially when he has some longstanding, slightly worrisome health issues, but it'll be interesting to see how much he's allowed to push it.

Will Sasaki be the Dodgers' second Tokyo Series starter?

This is the big, overarching question of Sasaki's spring. Although he came into camp humble, saying that his goal was to make the Opening Day roster, period, that seems like a given. Whether or not the Dodgers will put him on the mound against the Cubs in the second game of the Tokyo Series is the real question. MLB would want nothing more than to have Yamamoto in the opener and Sasaki in the closer, but it's still up to the Dodgers to decide.

After Sasaki's debut, there'll be just seven more spring training games for the Dodgers to get him facing hitters in actual competition. That's a very short on-ramp for a guy they might entrust a No. 2 spot to. It also seems like a given that Sasaki will at least appear in Tokyo in some capacity, but whether or not he'll be up on the marquee should be decided in the next week.