The Houston Astros opened 2026 by making a major investment in their pitching staff, signing Japanese right-hander Tatsuya Imai to a three-year contract worth up to $63 million.
While Imai may be unfamiliar to many Houston fans, the Astros are clearly betting on his upside. The deal carries one of the highest average annual values ever for a Japanese free-agent pitcher, trailing only Yoshinobu Yamamoto and former New York Yankees star Masahiro Tanaka.
Houston views Imai as a potential long-term fixture in the rotation. As he prepares for his Major League debut, here are four things Astros fans should know. At 27, Imai has already established himself as one of Japan’s most accomplished pitchers—and one of its fiercest competitors. Away from baseball, he is also known as an elite Mahjong player. Imai reportedly competed in a professional Mahjong league in Japan and defeated a professional player on his way to a tournament final last year. With the Astros clubhouse already known for card and board games, his arrival could add a new competitive edge off the field.
Imai drew interest from multiple MLB teams, including the Los Angeles Dodgers. Joining the defending champions would have paired him with fellow Japanese stars Yamamoto and Shohei Ohtani, but Imai opted for a different challenge. In a November interview with former Boston Red Sox pitcher Daisuke Matsuzaka, Imai cited admiration for Matsuzaka’s decision to carve out his own legacy rather than follow an established path. That philosophy appears to have guided his move to Houston.
Imai is also known for an unconventional uniform choice. In Japan, he has worn jerseys with small holes cut into the armpit area, believed to improve airflow. Whether Major League Baseball will allow the same modification remains to be seen. If approved, Astros fans could be treated to one of the more unusual fashion statements in recent memory.
Imai’s performance is what truly excites Houston. Over the past four seasons in Nippon Professional Baseball, his ERA, strikeout rate and walk rate improved each year. Last season, he led his league with a 27.8 percent strikeout rate and limited opposing hitters to a .172 batting average. The signature pitch in his arsenal is a rare “reverse slider,” breaking from left to right—an uncommon movement for right-handed pitchers. Combined with a rising fastball, the pitch has consistently baffled hitters. Though listed at just 5-foot-11 and under 180 pounds, Imai has shown that deception and precision can outweigh size. With Houston’s pitching development track record, the Astros believe they may have found their next rotation anchor.
As the 2026 season approaches, Houston is counting on its newest international addition to make a fast—and lasting—impact.
