HOUSTON -- The day before he was set to make his first Major League start, Astros pitcher Tatsuya Imai was in the bullpen at Daikin Park on Saturday afternoon and throwing 95 mph heaters.
It’s not exactly the same kind of routine pitchers typically keep before a start, but Imai isn’t your typical pitcher.
“That’s just normal for him,” manager Joe Espada said. “That’s pretty impressive.”
Imai, the former Japanese star who was signed by the Astros in January, will make his much-anticipated Major League debut in Sunday’s series finale against the Angels. Imai, 27, threw six scoreless innings in Grapefruit League action, striking out seven batters, and threw a splitter in live batting practice that wowed teammate Taylor Trammell.
If he’s able to “wow” an Angels lineup anchored by Mike Trout and Zach Neto that would be great news for the Astros, who signed him to a three-year, $54 million deal in January.
“There’s going to be a lot of fans [in the stands] and [facing] Major League hitters for the first time,” Imai said Saturday through an interpreter. “There’s definitely going to be some nervousness, but it’s up to me to use it as a positive, or as an enemy to myself. I just feel like if I can produce the way I did in Japan, it would be fine.”
Indeed, it would.
Imai was a three-time All-Star in NPB, including in both 2024 and ’25. He has emerged as an ace-level pitcher in Japan over the past several years -- he's posted an ERA under 3 and struck out more than a batter per inning in each of the past three seasons. But the ’25 season was arguably the best of his career. Imai went 10-5 with a career-best 1.92 ERA and 178 strikeouts in 163 2/3 innings and pitched in a combined no-hitter for the Lions.
In 2024, he went 10-8 with a 2.34 ERA and set career highs with 187 strikeouts and 173 1/3 innings pitched. Imai was posted by his Nippon Professional Baseball club, the Saitama Seibu Lions, on Nov. 19, and the Astros stunned baseball by signing him.
Seeing the kind of success teams like the Dodgers had signing players in Japan, the Astros planted a scout in the Far East and bolstered their efforts to become a player in that market.
“The Dodgers kind of led the way there and I’ve got an international company, so it was a pretty easy setup to give those guys a place to work and communicate back here in our system,” Astros owner Jim Crane said after signing Imai. “We’ll be moving pretty fast in Asia and continue to focus on that and evaluate all the talent over there so we can hopefully get some more over here to play and deepen the team.”
Imai’s two main pitches are his four-seam fastball and slider. His four-seamer averaged 94.9 mph in 2025 -- slightly above the average for an MLB right-handed starter (94.6 mph) -- and can reach the upper 90s. His slider averaged 86.2 mph and generated a 46 percent swing-and-miss rate.
During Imai's first live batting practice session in West Palm Beach last month, Trammell raved about his split-finger fastball, saying, “I’ve never seen a pitch like that before in my life.”
Astros second baseman Jose Altuve marveled at his slider, saying he couldn’t pick up the spin.
The Astros haven’t made many changes to Imai’s routine, allowing him to do what feels comfortable between starts. That included throwing a bullpen session on Saturday, less than 24 hours before he starts a game.
“We’ll see how he transitions to the U.S., and once we see that maybe he should consider doing other things that we’ll bring up, but right now his routine has been good,” Espada said. “He’s been feeling pretty good after bullpens and outings. His work in the weight room has been very excellent. If we see something that should be tweaked a little bit, we’ll bring it up. So far it’s been pretty good."
A group of Japanese reporters has followed Imai through the spring in Florida and into the season in Houston. He held a brief media availability prior to Saturday’s game in Japanese and English and was asked if he would have trouble sleeping before the biggest day of his professional life.
“I don’t really go to bed that early in general,” he said, “so I’m going to have to work on that tonight.”