Making their first splash in the Japanese free-agent market, the Houston Astros agreed to a three-year contract with right-hander Tatsuya Imai on Thursday, a league source told The Athletic, raising the ceiling of the Astros’ overhauled starting rotation.

According to a league source, the deal maxes out at $63 million and contains opt-outs after every season. Imai’s $18 million average annual value is the third-highest ever given to a Japanese-born pitcher, trailing only reigning World Series MVP Yoshinobu Yamamoto and former New York Yankees star Masahiro Tanaka.

Still, Imai’s NPB statistics and upside had many in the industry envisioning a longer-term contract for the 27-year-old right-hander.

Imai ranked No. 10 on The Athletic’s Free Agent Big Board and profiled as the best international pitcher in this year’s class of free agents. The Athletic’s Tim Britton projected Imai to earn an eight-year, $190 million contract.

Imai was officially posted to MLB teams Nov. 19, opening a 45-day signing window, which is set to expire on Jan. 2.

The Astros had informal discussions throughout the winter about Imai, team sources indicated, but it still registered as a surprise that Imai ended up in Houston. The free agent had other suitors, with the Chicago Cubs considered a strong contender to land Imai before he reached a deal with the Astros — a franchise not known for its investment in the Japanese market.

Imai is the first Japanese free agent signed by the Astros since Kaz Matsui inked a three-year, $16.5 million deal in 2008. The team did trade for outfielder Nori Aoki in 2017 and pitcher Yusei Kikuchi in 2023, but can now call itself a bigger player in the burgeoning Japanese market.

Interest in Imai centered on the idea that he is a 27-year-old with a fastball that sits in the mid-90s or higher and has a robust arsenal that features a slider, cutter, splitter and changeup. The slider profiles as his best secondary offering. Scouts have been divided on the quality of his other pitches — part of what could determine what type of starter he ultimately becomes in MLB. There are concerns his cutter and slider can blend together, or that his splitter can be inconsistent.

“The stuff’s really good,” an NL evaluator told The Athletic in November. “It’s a pretty deep arsenal. He has weapons to challenge and combat both-handed hitters in the big leagues.”

A Scott Boras client, the 5-foot-11 Imai throws from a low, deceptive arm angle, part of what allowed him to dominate Nippon Professional Baseball over eight seasons with the Seibu Lions. Imai posted ERAs of 2.04, 2.45, 2.34  and 1.92 over the past four seasons, coming to MLB with a statistical profiles that resembles Daisuke Matsuzaka’s last season in Japan.

Those who are most optimistic about Imai view him as a mid-rotation starter with the chance to have a higher ceiling, though nearly all evaluators agree he is not on the same level as the likes of Yoshinobu Yamamoto. There is a more pessimistic crowd that views Imai as a back-end starter who could even hold some level of reliever risk.

“I think he’s a mid-rotation guy,” the NL evaluator said. “I think on the right team, he’s like a No. 3, probably like a really good No. 4.”

For the Astros, Imai profiles as another high upside attempt at closing the gap between reigning American League Cy Young finalist Hunter Brown and the bevy of mid-rotation arms behind him. Houston is bracing for the loss of workhorse left-hander Framber Valdez in free agency and, as a result, made starting pitching its “top priority” this offseason.

Houston has already acquired Mike Burrows from the Pittsburgh Pirates and signed KBO sensation Ryan Weiss to an incentive-laden deal in hopes of solidifying its starting rotation behind Brown.

Imai’s market was strong, reflecting the fact he could boast at least two plus pitches with the capability to further refine his stuff. The recent relative success of similarly tiered Japanese pitchers such as Shota Imanaga could bode well for Imai’s transition to MLB.

One of the most fascinating players in this year’s free-agent class now gets the chance to show what he can do at the game’s highest level.