Astros’ Tatsuya Imai returns from IL with disaster start vs. Mariners, ERA now at 9.24

The Houston Astros were hoping for a much-needed reinforcement with the return of Tatsuya Imai from the injured list. They got something else instead.

Making the fourth start of his MLB career, Imai allowed 5 hits, 6 earned runs, 3 walks and 2 hit-by-pitches in a full meltdown against the Seattle Mariners. The Astros lost 10-2, sending them further into the basement of the AL West.

The disaster came in the fourth inning, which Imai opened by hitting Randy Arozarena and Luke Raley on back-to-back plate appearances. He then walked J.P. Crawford on four pitches.

Perhaps wanting to avoid an extra free pass, Imai kept his next pitch in the zone against Dominic Canzone. Unfortunately, Canzone took that middle-middle slider and deposited into the right-field seats at Daikin Park for his first career grand slam (video above).

Cue the boos in Houston.

After hitting Randy with my slider, I couldn’t adjust my command. My slider was above and down and I couldn’t put in the zone.

To Imai’s credit, the Astros left him in the game and he finished out the inning with no further damage. That doesn’t diminish just how bad a development his struggles are for the Astros.

What’s wrong with Tatsuya Imai?

The Astros bet big on Tatsuya Imai being at least the next solid player to come out of Japan, giving him a three-year, $54 million contract after an All-Star career with the Seibu Lions.

He looked solid enough in spring training, but then began his MLB career by getting chased by the Los Angeles Angels. He bounced back against the Athletics, showing off an intriguing “reverse slider” with 5 2/3 innings against the Athletics.

And then, in his third start, he allowed all but one batter to reach base against the Mariners. That was when the Astros opted to put him on the IL with “arm fatigue.”

Imai wouldn’t be the first player to struggle in MLB after a standout career across the Pacific, but he’s also offered no shortage of reasons for why the transition has so far been unsuccessful: the MLB mound has a different slope than he’s used to, the MLB ball is slick, the MLB mound was too hard, he’s not used to playing in colder temperatures like he did in Seattle, the players eat in the clubhouse instead of the hotel.

Whatever the causes, the biggest issue is a plain inability to throw consistent strikes. Imai walked 11 batters across 8 2/3 innings in his first three starts, with strikes on only 111 of 205 pitches. Those are not the numbers of a pitcher who survives in MLB.

The Astros theoretically worked on this with him, as manger Joe Espada told reporters before Tuesday’s game. The basic gameplan was to just throw strikes:

“Gameplan was simple. We encouraged him just to pound the zone. Be aggressive in the zone, challenge his hitters, just go after them with the best stuff.”

That obviously didn’t happen, as Imai threw strikes on 46 of 80 pitches. It probably shouldn’t have been a surprise, as he threw strikes on only 27 of 63 pitches for Triple-A Sugar Land in his last rehab start.

One change Imai did make was cutting his pitch mix down to the bare essentials. He had used a splitter and curveball sporadically in his first three starts, but the Mariners saw nothing but sinkers and sliders from him on Tuesday.

Espada confirmed Imai will make his next start as planned after the game.

Imai was never known as a command artist in Japan, with 4.4 walks per nine innings in his NPB career. However, he became intriguing to MLB teams precisely because he cut down on the walks, with only 2.5 per nine in his final season in 2025. And that progress appears to have disappeared after entering the Astros organization.

Given that the Astros are still missing starting pitchers Hunter Brown and Cristian Javier, among several other players, it’s pretty hard to overstate how bad Imai’s woes are for them.

There actually was a player who broke out of a major slump on Tuesday. That was Mariners star Cal Raleigh, who entered the game hitless in his last 36 at-bats.

The All-Star catcher walked in his first plate appearance then posted two more outs in his next two at-bats. With the slump at 0-for-38, he finally posted a single against Astros reliever Jayden Murray.

His teammates insisted on him keeping the ball in the aftermath.