SEATTLE — Desperation arrived after 27 pitches, most nowhere near Tatsuya Imai’s intended target. Number 28 sailed to the same spot as so many others, but Christian Vázquez tapped his helmet for a challenge anyway.

Imai’s misfired fastball missed the strike zone by a full inch, according to Statcast. Wasting a challenge in a 1-0 count against the game’s sixth hitter seemed illogical, but sometimes daring decisions are needed to interrupt an implosion. Vázquez is Imai’s personal catcher, in part, “just to continue to build some stability” for someone in need of it.

“I feel like it’s important for the transition of Imai to the major leagues,” Houston Astros manager Joe Espada said before the game.

Imai is making a move that few have mastered without mishaps. Doing so inside an organization that had never signed a Japanese player straight from Nippon Professional Baseball only complicates the task.

Easing it is the Astros’ foremost goal. They allowed Imai to dictate much of his spring training buildup, keep his peculiar schedule of bullpen sessions between starts, and maintain an open line of communication for feedback.

“We’re learning as we go,” Espada said.

Pairing Imai with Vázquez is another part of Houston’s plan. He caught each of Imai’s first two major-league starts, the first of which went awful and the second awesome. The third start on Friday tested the battery like never before. Vázquez tried every trick in the toolbox of his 12-year career, be it calling breaking balls while behind in the count, shouting encouragement after each misfire, and — when all else failed — challenging a pitch the entire stadium knew was a ball.

“Trying to do something,” Vázquez said. “I think it was close, in my eyes, but yeah, just trying to do something to help him.”

Nothing worked. Imai imploded at a time his team could ill afford it, amid a five-game losing streak and with the rest of Houston’s rotation in tatters. Imai procured one out, harnessed no command and further stressed an already-burdened bullpen. The Seattle Mariners seized the advantage, handing the Astros a 9-6 loss.

“I know we had the losing streak and players with injuries. I wanted to stop this losing streak,” Imai said through an interpreter. “But I wasn’t able to perform the starting pitcher’s job. That’s the sad part.”

Imai is the closest thing this shoulder-strained starting rotation has to a stabilizer, remarkable to consider but required by circumstance. Houston signed him this winter in hopes he could slot in the middle of its rotation. Indefinite absences from Hunter Brown and Cristian Javier have thrust Imai higher in the hierarchy and into an impossible position, one he’s paid to occupy but perhaps not ready to assume. Friday night at T-Mobile Park only furthered that thought.

Imai faced seven hitters. Four of them walked, and three scored. He hit a batter with the bases loaded and uncorked a wild pitch to force home another run. He threw 20 of his 37 pitches for balls, prolonging what must be a concerning trend for team officials.

Imai has walked 11 batters in his first 8 2/3 innings as a major leaguer. His ERA is 7.27. Only 54.4 percent of Imai’s pitches have been strikes, far below the major-league average of 62.8 percent. Even during Imai’s second start of the season, an encouraging outing in which he threw 5 2/3 scoreless innings against the A’s, he only tossed 61.7 percent of his pitches for strikes.

“It looked the same mechanically,” Vázquez said after Friday’s start. “But it was just way far from the zone.”

Across Imai’s final two seasons in NPB, a span of 337 innings, he walked just three batters per nine. During three appearances in spring training, Imai walked one batter. Now, he’s perhaps the most glaring problem on a pitching staff that surrendered a league-high 80 walks.

Reasons for Imai’s regular-season regression vary. He mentioned the mound at T-Mobile Park “was really hard,” and he failed to adjust. Pitching in 64-degree weather with a breeze is “not usual in Japan,” Imai said. The slickness of major-league baseballs has been an issue for him since spring training.

“In Japan, there’s only six stadiums we go around during the season, but here, we have to go to 30 stadiums and adjust to the mound in their stadium,” Imai said. “That’s what I have to figure out, how to adjust to those mounds.”

Graphic via Baseball Savant

Of the 20 four-seam fastballs he threw, one was called a strike. Without precise fastball command, Imai lives behind in the count and cannot unleash his trademark slider, even though Vázquez tried to call some while behind in counts. That didn’t work either.

Imai’s infrequent use of his curveball and changeup isn’t helping, but that may be a matter of comfort. Perhaps with more experience, his arsenal can expand, and his confidence will grow.

“As we know more about him,” Espada said, “we’ll continue to make adjustments with him.”

No other option exists, which is an eerie thought for a team teetering toward trouble.