RHP Tatsuya Imai To Be Posted
The Saitama Seibu Lions announced they will post RHP Tatsuya Imai this offseason. Once officially posted, Imai will have 45 days to negotiate a contract with an MLB club; if no agreement is reached, he will return to the Lions for the 2026 Nippon Professional Baseball (NPB) season.
Because Imai is over 25 years old and has accumulated more than six years of NPB service time, he will enter the MLB market as a traditional free agent, unlike Roki Sasaki, who faced different posting restrictions a season ago.
Photo Credit: Kyodo News
Imai had a strong season in 2025, posting a career-high 27.8% strikeout rate (NPB average: 19.6% strikeout rate) across 163.2 IP. For reference, Yoshinobu Yamamoto recorded a 26.6% strikeout rate in his final NPB season (2023) with the Orix Buffaloes. Imai’s strikeout rate steadily improved over the past three years (9.2 K/9 in 2023, 9.7 in 2024, and 9.8 in 2025), while maintaining impressive durability, logging at least 158 innings in each of the last three seasons. He excelled at limiting hard contact (16.5% hard-hit rate) and keeping the ball in the park (4.3% HR/FB).
His 53.8% ground-ball rate, combined with a well-rounded arsenal, aligns with the profile of MLB’s elite starting pitchers who pair swing-and-miss stuff with keeping the ball in the park. While Imai’s career walk rate remains slightly elevated, he has shown steady improvement, lowering it in each of the last four seasons, finishing 2025 with a 7.0% walk rate. Over his 963.2 career innings with the Lions, Imai owns a 3.15 ERA, 22.3% strikeout rate, and 11.5% walk rate.
Durability is key for MLB teams when evaluating NPB pitchers. Because NPB starters typically pitch once a week, the shift to a five-day rotation in MLB can be challenging, Kodai Senga being one recent example. To Imai’s credit, he has been among the most durable pitchers in Japan, ranking in the top ten in innings pitched every season since 2021 except for 2022. He was in the top ten in both innings pitched and strikeouts per nine innings (K/9) over the past three years.
The final factor in Imai’s profile is his age. Imai is only 27, and doesn’t turn 28 until May. Between his age and an intriguing four-pitch arsenal (headlined by a fastball in the mid-90s and a plus slider), there’s a lot to like in terms of how Imai’s success in NPB might translate against Major League hitters.
This upside led MLB Trade Rumors to place Imai seventh on their list of the offseason’s top 50 free agents, and they predicted a six-year, $150MM deal. While some evaluators view him more as a mid-rotation or back-end starter and possibly even a future bullpen arm, his age, track record, and improving command make him a strong candidate for a major deal this winter.
Imai will be one of the top pitchers on the market and surely a Mets target. With question marks surrounding their rotation, they will look to add a frontline starter, and might find what they’re looking for in Imai.
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