Astros Sign Tatsuya Imai

The Astros officially announced the signing of right-hander Tatsuya Imai to a three-year contract that allows him to opt out after each of the first two seasons. It’s reportedly a $54MM guarantee for the NPB star, who’ll collect a $2MM signing bonus and $16MM salary next year. He’s owed respective $18MM salaries between 2027-28. Imai, a client of the Boras Corporation, would reportedly escalate his 2027 salary by $2MM apiece at reaching 80, 90 and 100 innings next year. His ’28 salary would also climb by $1MM at each of those thresholds, meaning the total value can jump another $9MM.

Meanwhile, the Lions will receive a posting fee based on Imai’s $54MM guarantee. The current system for international postings gives the original club 20% of the first $25MM, 17.5% of the next $25MM, and 15% of anything over $50MM. That works out to $9.975MM, so the Astros are on the hook for just under $64MM between the contract’s guaranteed money and the posting fee. If Imai opts out next season, Houston will have committed $27.975MM for one year of his services. The Astros would also owe a 15% posting fee to the Lions on any escalators that Imai unlocks if he doesn’t opt out.

Imai was one of the top starters available in free agency and coming off a career-best 1.92 ERA season with the Saitama Seibu Lions of Japan’s Nippon Professional Baseball. It was reported several days ago that he was meeting with teams in-person in advance of his January 2 signing deadline. The Yankees, Mets, Cubs, Phillies, and Orioles were among the clubs interested in signing him, so the Astros are a bit of a surprise destination.

We at MLBTR ranked Imai No. 7 on our Top 50 Free Agents list and projected him for a six-year, $150MM contract. This deal with Houston comes in at half the length of that projection, with around a third of the guaranteed money. It appeared that Imai had other offers on the table for longer terms but lower AAVs (link via Mark Feinsand of MLB.com). The opt-outs in his deal with Houston allow him to try for a bigger contract in future offseasons if he can prove himself in MLB.

Imai is 27 years old (28 in May) and has pitched to a 3.15 ERA in 963 2/3 career NPB innings. He debuted in 2018 at age 20 and made 16 appearances (15 starts), but struggled with a 4.97 ERA. Those early struggles continued from 2019-20. In the pandemic season, Imai had a 6.13 ERA in 61 2/3 innings and walked more batters than he struck out, which resulted in him temporarily being moved to the bullpen. He rebounded in 2021, posting a 3.30 ERA in 158 1/3 innings with an improved strikeout rate, and he has stuck as a starting pitcher ever since.

That kicked off a run of dominance from 2022-25. After posting a 2.41 ERA in nine starts with the Lions in 2022, Imai followed up with a 2.30 ERA and a 24.4% strikeout rate in 133 innings in 2023. While he did walk 11.4% of hitters that year, his strikeout and walk numbers improved year over year from 2023-25. This year, he struck out 27.8% of hitters (highest among qualified NPB starters) and walked just 7.0%. His 20.7% K-BB rate was third-best in that league. Imai also did very well at keeping the ball in the yard, allowing just six home runs all season (0.33 HR/9) and inducing groundballs 48.3% of the time. Overall, he enters the majors with a higher ceiling and much-improved control compared to his early career.

In terms of stuff, Imai profiles as a mid-rotation starter in the majors. His fastball sits in the mid-90s and can reach 99 mph, and he also throws a slider, splitter, and changeup. His excellent performance from 2022-25 made him an attractive target in free agency, although some evaluators were concerned about his secondary stuff and past struggles with control. It seemed that industry opinion was mixed on whether he could succeed as a big-league starter, which resulted in the lower-than-expected guarantee.

At the time of his posting, a $150MM deal seemed like a real possibility. These days, teams value youth and upside and are willing to pay a premium to get it. Recent offseasons have seen players like Juan Soto and Vladimir Guerrero Jr. sign for over a decade and at least $500MM in guaranteed money. Among Asian players, right-hander Yoshinobu Yamamoto and outfielder Jung Hoo Lee came to the majors after their age-24 seasons and earned $100M+ deals. Imai is several years older than Yamamoto was when he signed and has a shorter track record as a front-of-the-rotation arm. While he was never going to match Yamamoto’s deal, Imai’s year-over-year improvement and relative youth were enough for the Astros to want him in their rotation.

Houston’s interest was not widely known, though it makes sense that they wanted another starting pitcher. Longtime ace Framber Valdez is currently a free agent. The team has had some discussions with Valdez’s camp, though the expectation is that he will sign elsewhere on a pricier contract. Hunter Brown was phenomenal in 2025, totaling 185 1/3 innings with a 2.43 ERA. That figure was third-best among qualified starters, trailing only Cy Young winners Paul Skenes and Tarik Skubal. He also posted an 85th-percentile strikeout rate and a 77th-percentile groundball rate. Altogether, he was worth 4.6 fWAR and finished third in AL Cy Young voting. He’ll return as the staff ace in 2026.

Behind Brown, the rotation looks shaky. Cristian Javier currently projects as the No. 2 starter. He owns a 3.66 ERA in 538 career innings, but he pitched just 71 2/3 innings from 2024-25 due to Tommy John surgery. In just 37 innings this year, Javier had a 4.62 ERA with a 21.7% strikeout rate and a 9.6% walk rate. He is under contract through 2027. Meanwhile, Lance McCullers Jr. has had his own injury troubles, pitching just 103 innings in the past four years and missing 2023-24 entirely. Even if he performs well in 2026, the team will monitor his workload carefully. The recently-acquired Mike Burrows will play some role. He had a 3.94 ERA in 96 innings this year with an impressive 16.4% K-BB rate, though his overall track record is fairly minimal.

The addition of Imai gives the Astros a durable No. 2 or 3 starter at an affordable rate. It remains to be seen how his strikeout and groundball potential will translate against major-league hitting, though the club is surely hoping he can maintain his performance from Japan. The signing brings the Astros’ projected payroll to $242MM, according to RosterResource. The club was a second-time luxury tax payor this year and is hoping to avoid paying it for a third time. The first luxury tax threshold for 2026 is $244MM, so the club will likely need to shed payroll if it wants to add to other areas of the roster.

With Imai now off the board, any clubs in need of a starter will need to look elsewhere. Dylan Cease was the top free agent pitcher entering the offseason and has since signed with the Blue Jays. Valdez, Ranger Suarez, Zac Gallen, Chris Bassitt, and Lucas Giolito are still available in free agency. Valdez and Suarez are front-of-the-rotation options, while Gallen, Bassitt and Giolito are cheaper, mid-rotation arms.

Jon Heyman of The New York Post first reported the Astros and Imai had agreed to a deal. ESPN’s Jesse Rogers was first on the three-year term with opt-outs after the first two seasons. Heyman reported the $54MM guarantee and $9MM in escalators at 80-100 innings, while Ronald Blum of The Associated Press was first on the signing bonus and specific escalator breakdown.