Seibu Lions starter Tatsuya Imai delivered an unforgettable performance Tuesday night, tossing a two-hit shutout against the Yokohama DeNA BayStars and setting a new single-game franchise record with 17 strikeouts. He broke the previous mark of 16 strikeouts set by club legend Daisuke Matsuzaka on September 1, 2004.
Tatsuya Imai. Future name to watch in @MLB. 🇯🇵 @MLBNetwork https://t.co/O0FxjYtuPr
— Jon Morosi (@jonmorosi) June 17, 2025
Imai made his Nippon Professional Baseball debut in 2018, pitching to a 4.81 ERA with 65 strikeouts in 78 ⅔ innings. He continued to receive opportunities in the rotation, but early struggles persisted, and he finished with a 4.32 ERA in 2019 and a 6.13 ERA in 2020, when he issued more walks than strikeouts. In 2021, Imai made a career-high 25 starts and turned in a much-improved 3.30 ERA. Though limited to just nine starts in 2022, he impressed with a 2.41 ERA and a 24.8% strikeout rate. His true breakout came in 2023, when he posted a 2.30 ERA with a 24.4% strikeout rate over 133 innings. He built on that success in 2024, delivering a 2.34 ERA and 26.3% strikeout rate in a significantly larger workload of 173 ⅓ innings.
Despite the better results, Imai continued to struggle with control, carrying a career walk rate above 12% entering the 2025 season. He is one of the most electric, yet volatile, starters in NPB issuing three or more walks in 15 of his 25 starts in 2024. So far in 2025, the 27-year-old has been in dominant form all season, completing at least seven innings in all 12 of his starts and allowing two or fewer runs in all but one. He now boasts a stellar 1.17 ERA, 0.75 WHIP, and 1.80 FIP over 92 innings, while ranking second among qualified NPB pitchers with a 30.6% strikeout rate, behind only Livan Moinelo who had an 18-strikeout game earlier this month. His 6.5% walk rate is by far the best of his career.
The right-hander’s streak of 16 consecutive high-quality starts of seven or more innings pitched and two or fewer earned runs recently came to an end in Hiroshima, but he responded in remarkable fashion with a career-best 17-strikeout performance on June 17, 2025 to set the Seibu Lions single-game record.
All 17 of Tatsuya Imai’s Ks tonight
— Yakyu Cosmopolitan (@yakyucosmo) June 17, 2025
He saw just 28 batters in a complete game effort, surrendering only two hits – both to Shugo Maki – and struck out an astounding 61% of the hitters he faced, generating 27 swinging strikes. Of his 123 total pitches, 65 were strikes. He threw 65 four-seam fastballs, 41 sliders, 15 splitters, one curveball, and one changeup. He averaged 94.5 mph on his fastball, peaking at 98 mph on the final pitch of the night as the Lions won, 3-0.
Seibu Lions All-Time Single-Game Strikeout Leaders
Tatsuya Imai 17, Today 🆕
Daisuke Matsuzaka 16, 9/1/04
Kimiyasu Kudo 15, 4/17/87
Daisuke Matsuzaka 15, 9/2/99
Shinsaburo Tawata 15, 9/7/16pic.twitter.com/wlo1HAj353— Yakyu Cosmopolitan (@yakyucosmo) June 17, 2025
Perhaps the most iconic strikeout of the night came in the eighth inning when he fanned Maki, who had previously singled and doubled off him. Imai then broke into a “sword celebration,” which is widely associated with controversial firebrand Trevor Bauer, who happened to be the opposing starter in the game.
A native of Tochigi, Tatsuya Imai is on track to be selected for Samurai Japan’s 2026 World Baseball Classic roster, where he’s expected to play a key role in the rotation, alongside other superstars like Yoshinobu Yamamoto, Kodai Senga, Shota Imanaga, and Hiroya Miyagi. While the timeline for his move to Major League Baseball remains uncertain, a posting by 2027 appears likely.
Seibu is expected to approve the posting request of Imai’s teammate and fellow starter Kona Takahashi this offseason after previously denying it, which could lead the club to retain their ace for at least one more year. Should Imai make the move to MLB in the near future, there’s already speculation that he could command a contract exceeding $100 million given his relatively healthy track record and overpowering stuff.
WBN Japan: https://worldbaseball.com/league/japan/
Photo: Wiki Commons user Masatokun555 on May 16, 2023
