Roki Sasaki: Baseball’s Most Puzzling Ace in the Making

 

Roki Sasaki can be great and then can be terrible.

Roki Sasaki is one of those pitchers where the hype was too much for an unpolished prospect.  Before he even threw a pitch in the majors, everyone already knew about the fastball, the splitter, and the nickname “The Monster of the Reiwa Era.” He was not just some random good pitcher from Japan either. In NPB with the Chiba Lotte Marines, he had a 29-15 record, a 2.10 ERA, and 505 strikeouts in 394.2 innings. That is 11.5 strikeouts per 9, which is ridiculous in any league, even more so when you remember he was still extremely young. So when he came over to the Los Angeles Dodgers, the expectation was not just that he would be good. The expectation was that he would become a legit ace right away. But, that was wrong in so many ways. He struggled mightily, even causing him to be mocked for crying. Did he really cry? Recently, he made comments about a most recent event in which he was said to be crying and duly noted it was just his face to blame. Let’s leave it at that.

His perfect game in 2022 is still the thing that makes people talk about him like he is not normal, and to be fair, it was not normal. At only 20 years old, Sasaki threw a perfect game for Chiba Lotte, struck out 19 hitters, and struck out 13 batters in a row. That’s the kind of start that turns a pitcher from a prospect into a myth. It was not just one good night either. In 2022, he finished with a 2.02 ERA and 173 strikeouts in 129.1 innings. In 2023, he somehow had an even lower 1.78 ERA, though he only threw 91 innings. The talent was always obvious, but even back then, there was still the question of health and whether he could handle a full year in the MLB level.

Sasaki made his Dodgers debut on March 19, 2025, against the Chicago Cubs in Tokyo. He went 3 inn, allowed only 1 hit and 1 earned run, and struck out 3, which sounds fine until you see the 5 BB. That’s basically the whole problem with him so far. The stuff can look nasty, but the command just disappears for stretches. In 2025, he had a 4.46 ERA in 36.1 inn, with 28 K and 22 BB. That walk number is ugly. A 13.7% walk rate is not something you can just ignore, especially for a guy who had so many expectations like he had coming into the league.

After the Tokyo series in March, he experienced a little be of shoulder tightness, which was thought to be not serious, but was treated with careful hindsight from the coaching staff in which they limited the amounts of pitches he threw until he was shutdown in May and went to the IL for a short period of time. Then, when hope seemed to be lost, Roki had a post-season resurgence. He became the Dodgers postseason closer and delivered a series of unforgettable performances.

WILD CARD SERIES vs Reds

Coming into the game, he looked like he had something to prove. 1 IP, 0 R, 2 K. It was only one inning, so obviously you cannot go crazy over it, but for Sasaki’s first MLB postseason appearance, this was exactly what the Dodgers wanted to see. The fastball had that triple digit life again, the splitter looked like the pitch that made him famous in Japan, and he actually challenged the Reds hitters instead of nibbling around the zone. After how uneven his regular season was, this inning mattered more than the box score probably shows.

NLDS vs Phillies

Game 1 — His Breakout MLB Moment

Line: 3 IP, 0 R, 4 K. This was probably the first time in the majors where Sasaki really looked like the pitcher everyone kept hyping up. He retired 10 straight hitters, which is not something that just happens by accident in October. The 100 mph fastball was there, but the bigger thing was the command. It looked way more under control than it did during the regular season. No four strikeout streak or anything like his Chiba Lotte days, but three innings of pure dominance against the Phillies is still a huge statement.

Game 4 — Lockdown Setup Work

Line: 1 IP, 0 R, 1 K. This was not the loudest outing, but it was the kind of inning a championship team needs. A clean eighth inning in a closeout game is not nothing. He did not make the Dodgers sweat, he did not lose the zone, and he helped LA close out the series. For a guy who had been such a question mark earlier in the year, that is a pretty big deal.

NLCS vs Brewers

Game 1 — The Only Bump

Score when he entered: Dodgers leading 5–3. Line: 0.2 IP, 1 R, 2 BB, 1 H. This was his roughest outing of the postseason, and honestly it looked like the regular season version of Sasaki came back for a second. The command wavered, the Brewers started threatening, and suddenly the inning got uncomfortable fast. That is always the scary thing with him. When he is in the zone, he looks almost unhittable. When he starts walking people, everything falls apart quickly. LA survived, but this was the reminder that he was still not a finished product.

Game 4 — Back to Dominance

Line: 1 IP, 0 R, 2 K. Then, just like that, he went right back to looking nasty again. Sasaki slammed the door in the eighth and helped set up Ohtani’s legendary 3-HR, 6-scoreless masterpiece. Obviously Ohtani was the story of that game, and he should have been, but Sasaki doing his job there still mattered. You do not get to have a legendary moment if the bullpen gives the game away before it can happen.

WORLD SERIES vs Blue Jays

Game 2 — First WS Save

Line: 1 IP, 0 R, 1 K. The Dodgers went up 2–0 in Toronto, and Sasaki getting the save there is honestly kind of crazy when you think about where he was earlier in the season. A few months before this, people were questioning if he could even be trusted in big spots. Now he was closing out a World Series game. That is how fast October can change the way people talk about a player.

Game 5 — The 18-Inning Epic

Line: 2 IP, 0 R, 3 K — Save #2. In the longest World Series game ever, Sasaki shut down Toronto’s momentum and kept LA alive. That is not a normal spot for any pitcher, especially someone who had been questioned all season. At that point in an 18-inning game, one bad pitch can basically ruin everything. Instead, he gave the Dodgers two scoreless innings and made it feel like the postseason version of him was becoming a completely different story.

 

Game 7 — The Championship Closer

Line: 2 IP, 0 R, 2 K — Save #3. With the Dodgers clinging to a 5–4 lead in the 11th, Sasaki delivered two perfect innings to secure the title. That is not just a nice outing. That is the kind of moment that completely changes how a rookie year gets remembered. A Japanese ace closing out a World Series on foreign soil is already an instant classic, but with Sasaki it hits even harder because of how rough the road was before October. Without this run, people talk about the walks, the injury, and the disappointment. With it, now the season looks like a rough beginning before a massive breakout.

 

2026 Back to being Bad

 

The 2026 numbers are weird because they are better in some areas, but also somehow worse in the areas that actually scare you. Through 15 starts, he is 3-5 with a 5.40 ERA, 1.40 WHIP, 75 strikeouts, and 32 walks in 75 innings. The strikeout rate is basically 9.0 K/9, which is fine, but for a guy with Sasaki’s hype, fine is not really what people were expecting. The bigger problem is the home runs. He has already given up 17 homers, which comes out to 2.04 HR/9. For someone throwing a 97.5 mph fastball with a splitter that was supposed to be nearly unhittable, that is the part that makes you pause. It is not just the walks anymore. When he misses, he is getting hit, and when he gets hit, he gets hit very hard.

Baseball Savant kind of shows why watching him is so confusing. The fastball velocity is still elite at 97.5 mph, so it is not like the arm suddenly disappeared. The extension is also really good at 7.1 feet, meaning the ball probably feels even harder for hitters than what the radar gun says. His whiff rate is 27.9%, which is above average, and the chase rate is 31.5%, so hitters are still offering at stuff out of the zone. But then you look at the damage and it is not pretty. A 12.9% barrel rate, 45.6% hard-hit rate, and 4.77 xERA tells you that hitters are not just making soft contact when they do touch him. The stuff still looks real, but the results say he is still nowhere close to being a finished ace.

To put it into perspective, Sasaki hasn’t been the instant superstar some people thought he would be. That does not mean he’s a bust just yet, but it does mean the Dodgers are dealing with more of a project than a plug-and-play ace right now. He still has the fastball, he still has the splitter, and he still has the kind of arm talent that very few pitchers in the world have. But MLB hitters aren’t going to just miss because of reputation. If he leaves fastballs in bad spots, they are going to hit them. If he falls behind in counts, they are going to sit on something. He’s finding out real fast that the NPB and MLB aren’t in the same league.

At the same time, I still think it would be dumb to count him out this early. He is only going to be 24 this November, and even with all the ugly numbers, there are still flashes where you can see why everyone was so excited about him in the first place. The Dodgers have the luxury to be patient simply because their roster is stacked, and they do not need him to be the ace of the staff. They just need him to be serviceable. But Roki is young. He can learn and adjust. But if Sasaki wants to become the guy people thought he was going to be, the command has to improve, the home runs must come down, and he has to show he can hold up as a starter over a full season. He needs to dig deep down into himself and find a way to maneuver in the top baseball league in the world.

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