It’s Roki Sasaki season.
Ever since the news surfaced that the 23-year-old Japanese sensation is making his way to the United States this winter, Sasaki has been the talk of the town in the baseball world. A potential ace available at a reasonable cost, this long-limbed pitcher has grabbed the attention of all 30 MLB teams.
As we wait for the mysteries of Sasaki’s free agency to unfold, let’s take a closer look at him as a player.
What kind of pitcher is he? What pitches does he throw and at what speeds? Are there any concerns about injuries or durability? Who in the MLB can we compare him to? What are realistic expectations?
Let’s analyze the data and create an in-depth scouting report on the most sought-after arm this offseason.
Sasaki’s first experiences in professional baseball
Sasaki has been in the spotlight since his high school days when he hit 101 mph with his fastball, breaking Shohei Ohtani’s record for the fastest pitch by a Japanese high school pitcher. Despite receiving interest from MLB teams straight out of high school, Sasaki chose to play in NPB for the Chiba Lotte Marines, who picked him first overall in 2019.
He opted to sit out the 2020 season to give his arm a break, as advised by his team. In 2021, he emerged as one of the top pitchers in Japan’s premier league. The following season, Sasaki made a name for himself by throwing a perfect game and retiring 52 consecutive batters at one point. All of this before turning 21. He even represented Japan in the World Baseball Classic, where he showcased his talent before being slightly derailed by a few hits and a three-run homer.
Back in NPB, Sasaki continued to excel in 2023 and 2024, although he struggled to stay healthy, pitching a total of 202 innings over the two seasons.
Sasaki’s 2024 season
During the past season, Sasaki pitched 111 innings with a 2.35 ERA, but his performance was affected by a decrease in his stuff. Most notably, his fastball was nearly 2 mph slower on average compared to the previous year. He also missed several starts due to an unspecified arm problem, which likely contributed to his reduced velocity. Despite this, Sasaki delivered an outstanding performance in his final outing of the season, throwing eight shutout innings with nine strikeouts in the playoffs.
Durability and injury considerations
If Sasaki were a standard free agent without contract limitations, there would be more discussion about his durability issues. Over four NPB seasons, he averaged less than 100 innings per year. While this may not be a major concern in today’s game where pitchers throw fewer innings, it’s worth noting that Sasaki has yet to handle the workload expected of a top-tier pitcher.
Unfortunately, it’s almost certain that Sasaki will require arm surgery, either on his elbow or shoulder. Nearly every MLB starter who throws as hard as him has undergone surgery at some point. Teams interested in signing Sasaki are aware of this risk, but due to his affordability, his durability won’t be as scrutinized as it would be for a higher-priced player like Yoshinobu Yamamoto from last year.
Sasaki’s pitching repertoire
Sasaki primarily relies on three pitches: a four-seam fastball, a splitter, and a slider. He used to throw a curveball, but has abandoned it in recent seasons.
In 2024, Sasaki used his fastball around 50% of the time, the splitter about 28%, and the slider 25%. This marked a significant increase in slider usage compared to previous years. As he transitions to MLB, the slider is expected to be a key weapon against right-handed hitters. However, very few MLB pitchers rely on their splitter as frequently as Sasaki does.
The fastball
Despite the recent drop in velocity, Sasaki still throws exceptionally hard for a starting pitcher. His average speed of 96.9 mph in 2024 would have ranked among the top MLB starters last season. His 2023 average of 98.8 mph would have been just behind Skenes’ 98.9.
What sets Sasaki’s fastball apart is not just its speed. It also possesses a rare combination of horizontal and vertical movement, making it challenging for right-handed hitters to connect with.
Some current MLB players who offer reasonable comparisons to Sasaki include Skenes, Hunter Greene, Spencer Arrighetti, and Jeff Hoffman. Skenes is the only starter in the league with similar velocity to peak Sasaki pre-2024. Greene has the speed and movement but less horizontal action. Arrighetti has a similar pitch shape but operates at a lower velocity.
Sasaki, the reliever, possesses a fastball that is comparable to Sasaki’s in shape, although not as impressive. Even if Sasaki’s fastball never reaches its pre-2024 levels, it remains an exceptional pitch. However, if he regains his 99 mph velocity, it will surpass even Skenes’ prowess.
The splitter in Sasaki’s arsenal is like no other. While most splitters move downward and towards the arm-side, Sasaki’s splitter has minimal horizontal break, moving straight down. His ability to adjust the pitch based on the hitter’s handedness makes it a formidable weapon. Whether facing lefties or righties, Sasaki’s splitter presents a unique challenge for hitters.
On the other hand, Sasaki’s slider is still a work in progress. Despite increased usage in 2024, it will need more consistency to become a reliable pitch, particularly against right-handed batters.
In summary, Sasaki’s potential is immense, with a rare combination of current skill and future growth. Comparable to Skenes, who made a significant impact in his MLB debut season, Sasaki’s fastball metrics outshine Skenes’, although the latter has a more imposing presence. Despite inevitable challenges and injuries, Sasaki’s data-driven hype is well-founded.