The Houston Astros have made a major splash in the MLB free agency market by agreeing to terms with star Japanese pitcher Tatsuya Imai on a three-year contract. According to a report by ESPN, the deal guarantees $54 million and could reach $63 million with incentives, positioning it as one of the richest for a posted Nippon Professional Baseball (NPB) pitcher.

Contract details and impact

Reported first by MLB Network and confirmed by ESPN, the agreement includes opt-outs after each season, giving the 27-year-old right-hander flexibility. The structure features a base of $18 million annually, with potential bonuses pushing it to $21 million per year based on innings pitched.

This will mark the second-highest average annual value for a Japanese pitcher in MLB history, trailing only Yoshinobu Yamamoto’s $27.08 million AAV on his 12-year, $325 million pact with the Los Angeles Dodgers.

Unlike domestic free agents such as Framber Valdez, the Houston Astros will avoid losing draft picks since Imai will come via the posting system. Notably, Houston will owe the Saitama Seibu Lions a release fee calculated on the contract value.

Tatsuya Imai’s NPB performance

Tatsuya Imai had a remarkable 2025 season with the Seibu Lions, going 10-5 with a 1.92 ERA over 163â…” innings. He struck out 178 batters against just 45 walks, dropping his walks per nine from 5.1 in 2022 to 2.5 last year.

His fastball sits 93-97 mph, touching 99, paired with an effective splitter and a unique arm-side slider that generated a 45% miss rate. Highlights included eight innings in a combined no-hitter on April 18 and a 17-strikeout game on June 17, breaking a team record.

Over eight NPB seasons, Imai compiled a 58-45 record, 3.15 ERA, and 907 strikeouts in 963â…” innings as a three-time All-Star.

Houston Astros’ strategy

Houston Astros, seeking rotation depth amid uncertainty with veterans like Valdez, will land a high-upside arm without long-term commitment risks thanks to the opt-outs. Imai projects as a mid-rotation staple with ace potential, bolstering a staff known for developing pitchers.

This signing will highlight the growing influence of NPB talent in MLB, following successes like Yamamoto and Shota Imanaga. As the Astros aim to contend in 2026, Imai’s addition signals aggressive intent in a competitive AL West.