Arguably the most talented pitcher in the world not currently pitching in MLB will make his debut in 2025 after the Chiba Lotte Marines announced this weekend that they will be posting the 23-year-old Roki Sasaki.
Sasaki has been one of the most discussed pitchers in the world over the past few seasons. He showed his upside across five seasons with the Marines in Japan, posting a 2.02 ERA in 414.2 innings of work, with 524 strikeouts and a sterling 2.0 walks per nine. Sasaki can comfortably sit in the high-90s with his fastball and has a slider and splitter to round out the arsenal, which Eno Sarris' Stuff+ metric rated as a top-10 MLB mark when he pitched up in the 2023 World Baseball Classic. It's a legitimate ace profile when just looking at the stuff, and Sasaki is going to be one of the most sought-after pitchers on the market this offseason – in large part because he will be subject to the international bonus pool, limiting how much he can make. This won't be a Yoshinobu Yamamoto situation where Sasaki signs for a comparable contract to what Corbin Burnes is likely to get this offseason; he's going to sign a minor-league deal, though he will almost certainly do so with the intention of pitching in the majors in 2025 and beyond.
It's an incredibly exciting profile, and from a Dynasty perspective, it's enough to make Sasaki one of the 10 or so most valuable pitchers in the league. This is a 23-year-old who, while unproven at the MLB level, has been one of the best pitchers in the best league outside of the United States, and should clearly be valued ahead of any other pitcher who has yet to make their MLB debut.
But I'm just a bit more skeptical of his immediate value for 2025 Fantasy Drafts. Sasaki's stuff took a step back in 2024 amid a couple of arm injuries, with his fastball velocity dropping from 98.9 mph in 2023 to 96.9 mph in 2024. His strikeout rate dropped from 39.1% in 2023 to 28.7% in 2024 -- still a very strong number, better than anything Yamamoto managed in his final three seasons in Japan -- and his ERA rose from 1.78 to 2.35.
But hey, a 2.35 ERA is still pretty special, right? Well, this is where we have to account for the massive deadball era the Nippon Professional Baseball League has been mired in. Yamamoto's final season in 2023 saw him post a 1.16 ERA in a league where the average was 3.15, leading to an absolutely bonkers 272 ERA+; his actual mark in his MLB debut in 2024 was 129. That's the same mark Sasaki posted in his final season in Japan. While that's an awesome number -- among MLB qualifiers in 2024, only 10 had a better one -- it's not quite as impressive as the surface level number might make you think. Especially when you compare it to how some of the other high-profile Japanese import pitchers over the past few years have fared before they came to MLB:
Roki Sasaki
- 2022: 156 ERA+
- 2023: 177 ERA+
- 2024: 129 ERA+
Yoshinobu Yamamoto
- 2021: 250 ERA+
- 2022: 188 ERA+
- 2023: 272 ERA+
- 2021: 127 ERA+
- 2022: 165 ERA+
- 2023: 120 ERA+
- 2020: 175 ERA+
- 2021: 130 ERA+
- 2022: 167 ERA+
Yamamoto was putting up scale-breaking numbers, while Sasaki looks more like Senga and Imanaga. In fairness, both were also seven years older than Sasaki during the stretches being covered here, so there's plenty of room to project further growth on Sasaki, so we should be more excited about him than we were about either of those two. And the fact that Sasaki dealt with injuries the past two seasons – an oblique issue in 2023 and then an undefined arm injury in 2024 – surely impacted his effectiveness at least somewhat.
But that also brings up a key reason to keep expectations for Sasaki in check, at least for 2025. He's coming off a season that was, if not ruined by injuries, certainly adversely impacted. He'll be making his MLB debut after his fastball lost 2 mph of velocity last season, and he has been limited to just 33 starts and 222 innings over the past two seasons combined, with a career high of 129.1 back in 2022.
That's not an unusual workload, even for a young pitcher in the United States, but it does limit how much we can reasonably expect from Sasaki in 2025. No matter where he pitches, you have to assume his team will be careful with his workload, trying to avoid having him pitch on four days' rest, something he'll have little to no experience doing in Japan. The Cubs did that with Imanaga, and he still managed to make a big impact for Fantasy in 2024, tossing a 2.91 ERA over 173. Innings, but he had also reached 170 innings in his career in Japan once before, with at least 140 innings in seven of eight seasons to open his career.
Of course, you don't need to look far to find an example of a rookie making a huge impact for Fantasy in fewer than 140 innings – Paul Skenes was the No. 9 SP in Fantasy in 2024 in just 133 innings, after all. And Sasaki might have that kind of upside, though he doesn't necessarily have the arsenal depth Skenes does. A more reasonable comparison might be to Garrett Crochet, who wasn't quite as dominant as Skenes, but still finished as a top-30 SP in 146 innings despite winning just six games on the White Sox.
The problem is, 146 innings might just be the ceiling for Sasaki as a rookie, and there's no guarantee it goes as well for him as it did for either Crochet or Skenes, or Yamamoto, Senga, or Imanaga. The talent is there, and I'd bet on Sasaki being an impact arm right away for Fantasy. But there's enough working against him immediately that I don't think he necessarily needs to be drafted as an ace for Fantasy.
Especially in a year where the SP market actually looks quite deep. I think Sasaki is a better talent than someone like Bryce Miller or Hunter Greene, but can I really justify ranking him ahead of those guys coming off breakout seasons at the MLB level? Well, their ADP in very early NFBC drafts is SP21 and SP23, respectively, so I think the best you can do with Sasaki is rank him as a high-end No. 3 starter for Fantasy. And even in the lower end of the No. 3 SP range of ADP, you have guys like Tyler Glasnow and Spencer Strider, with similar boom/bust potential. And while I can see the case for ranking Sasaki ahead of them right now based on the fact that, well, he's the only one of the three who isn't currently injured, they are also two proven aces at the MLB level. Something Sasaki, for all his talent, isn't.
I suspect Sasaki is going to be someone who garners a lot of excitement in Fantasy drafts, and even if I rank him as a higher-end SP3, there's a decent chance that simply won't be high enough to end up drafting him in most leagues. It would be a bummer to miss out on Sasaki, and I might get a strong enough sense of FOMO to justify the cost in at least one draft in the long run. But, for all Sasaki's talent, he's still unproven at the MLB level and will have obvious limitations on his ceiling for 2025. Given that, he simply can't be one of the two pitchers you build your staff around.
At least, he won't be for me.
