Roki Sasaki Dodgers Debut: What To Expect From MLB’s No. 1 Prospect
Image credit: (Photo by Mary DeCicco/MLB photos via Getty Images)
Roki Sasaki is set to make his long-awaited Dodgers debut Wednesday morning at 6 a.m. ET against the Cubs at the Tokyo Dome as part of MLB’s Tokyo Series in Japan. His outing marks the culmination of a winter of speculation and intrigue after Los Angeles beat out the rest of the sport to land Sasaki for just $6.5 million on the international signing market.
The 23-year-old instantly became MLB’s No. 1 prospect–he’s eligible because he signed as a minor league free agent and is not subject to foreign professional standards–and the “Monster of the Reiwa Era” has long captivated fans and scouts alike with a fastball that nears triple digits and a scintillating splitter.
Here’s what you should expect from Sasaki when he takes on the Cubs.
Roki Sasaki’s Background
Like most legends, Sasaki’s story begins with tragedy. When he was nine, his father and grandparents were killed by a tsunami caused by the massive Tohoku Earthquake. Sasaki, his mother and two brothers lived in a nursing home before resettling in the small coastal city of Ofunato. Sasaki began playing baseball as an escape and blossomed into the country’s top amateur pitcher. At Ofunato High School, he reached 101 mph to break Shohei Ohtani’s national high school record and earned the nickname “The Monster of the Reiwa Era.”
He received further acclaim when he threw a 12-inning complete game with 21 strikeouts on 194 pitches in a regional qualifier for Koshien, Japan’s famed national high school tournament. Chiba Lotte selected Sasaki with the first overall pick in the 2019 Nippon Professional Baseball draft and, cognizant of protecting his arm, sat him during the 2020 season and used him sparingly in 2021. Once Chiba Lotte turned him loose in 2022, Sasaki became an international sensation. At 20 years old, he pitched a perfect game with an NPB-record 19 strikeouts. He threw eight more perfect innings his next start and finished the year with 173 strikeouts, second-most in the Pacific League.
He made his U.S. debut at the 2023 World Baseball Classic semifinals against Mexico and averaged 100.5 mph on his fastball, helping lead Japan to the gold medal. Sasaki made only 15 starts in 2023 due to a torn left oblique and 18 starts in 2024 due to shoulder fatigue, but he starred when healthy. He went 10-5, 2.35 with 129 strikeouts and 32 walks in 111 innings for Chiba Lotte in 2024 and was posted after the season.
Roki Sasaki Scouting Report
Sasaki has a lean, projectable, 6-foot-4, 202-pound frame and an explosive arsenal that rivals any in Major League Baseball. His fastball sits 96-100 mph and touches 102 with remarkably little effort and jumps on hitters with late explosion. His fastball occasionally flattens out and plays below its raw velocity, but it’s still a plus-plus pitch he can blow by hitters with pure power.
Sasaki’s primary weapon is a devastating splitter that most observers consider the best in the world. His splitter comes out of the same slot as his fastball at 88-91 mph before diving hard into the ground to draw foolish swings and misses from both lefthanded and righthanded batters. He cuts his splitter in both directions and throws it with so much power and movement that catchers sometimes struggle to handle it. Sasaki mostly uses his fastball to get ahead of hitters and his splitter to finish them, but he began integrating his slider more last season to become a more complete pitcher.
His slider sits 83-85 mph with late, vertical snap and projects to be a plus offering as he throws it with more conviction and confidence. He also drops in an occasional 80-81 mph curveball to steal a strike early in counts. Sasaki ties his head-turning arsenal together with plus control and is an elite competitor who goes right after hitters.
The only source of concern is his health. Sasaki’s velocity dropped last year as he battled arm soreness and he has never pitched more than 129.1 innings in a season. A lack of upper body strength causes timing issues in his delivery and puts excess stress on his shoulder and elbow.
Roki Sasaki Quick Hits
- Forget just prospects. Sasaki is already one of baseball’s 100 best players
- The rich could get richer — there’s a chance Sasaki nets the Dodgers an extra draft pick
- With Sasaki in the fold, the Dodgers could have baseball’s deepest pitching staff ever
- Here’s how Sasaki and teammate Shohei Ohtani compared as pitchers at the same age
- The Sasaki signing process threw the international market into turmoil
- Check out this deep dive into Sasaki’s pitch data
- Roki Sasaki’s close-up at the WBC was something to remember
How Have Other Top Pitching Prospects Fared In Their Debut?
Sasaki is in rare territory as a pitcher at the top of the Top 100. The last pitcher to rank No. 1 in our flagship preseason ranking was Daisuke Matsuzaka in 2007. That said, several recent top arms went on to enjoy fairly successful debuts. You can find the top pitching prospect in each of the last five preseason Top 100s below.
2024 – Paul Skenes, RHP, Pirates
Top 100 Rank: 9
MLB Debut: May 11, 2024 against the Cubs
Skenes’ debut last season against the Cubs was appointment viewing. He hit triple-digits 17 different times en route to striking out seven batters over four innings, surrendering six hits and three runs. Skenes only got better from there. He allowed more than two runs in a start just once—giving up four runs over six innings to the Dodgers in August–to finish 11-3, 1.96 and win NL Rookie of the Year.
2023 – Andrew Painter, RHP, Phillies
Top 100 Rank: 5
MLB Debut: TBD
Tommy John surgery has slowed Painter’s ascent to the majors, but he once again ranks among the top pitching prospects in the sport this year and is expected to reach Philadelphia at some point in 2025.
2022 – Grayson Rodriguez, RHP, Orioles
Top 100 Rank: 6
MLB Debut: April 5, 2023 against the Rangers
Rodriguez struck out five Rangers hitters over five innings in his 2023 debut while allowing two earned runs. He got better as the start went on, retiring 13 of his final 15 hitters, but Rodriguez’s first stint in the big leagues was rocky. He fared much better upon his return to Baltimore in mid July and has the talent of a potential front-of-the-rotation type pitcher. Baltimore needs Rodriguez to find a way to stay healthy and stabilize its rotation in 2025.
2021 – Sixto Sanchez, RHP, Marlins
Top 100 Rank: 6
MLB Debut: Aug. 22, 2020 against the Nationals
Sanchez earned a win in his big league debut, allowing three runs on six hits over five innings against the Nationals. He quickly became a trusted arm in Miami’s pitching staff, posting a 3.46 ERA over 39 innings and even started a postseason game. Sanchez has yet to recover that form because of shoulder injuries. He did not return to the majors again until 2024, where he struggled before right shoulder inflammation ended his season. He is now pitching in the Mexican League.
2020 – MacKenzie Gore, LHP, Padres
Top 100 Rank: 6
MLB Debut: April 15, 2022 against the Braves
Gore struck out three Braves hitters and allowed two runs over 5.1 innings in his big league debut. He battled his command at times during his rookie season, but the third-overall pick in the 2017 draft has settled into his new home in Washington following the Juan Soto trade and was announced as the Nationals’ 2025 Opening Day starter.
