Astros’ Tatsuya Imai leans on a left heel to turn the corner in duel with Jacob Misiorowski

HOUSTON — Every fifth or sixth day, thresholds are crossed, limits are tested and new wrinkles are unearthed. Each of Tatsuya Imai’s starts is instructive, even those that have tried patience and prompted panic. His response to them is important, an indicator of how he will handle the tumultuous nature of a major-league season.

Imai’s imperfect introduction has lowered expectations, but not diminished his importance to a Houston Astros team trying to recover from a 19-30 start. For that to occur, Imai must morph into something resembling a reliable starting pitcher — one with confidence in both his stuff and himself.

Steps toward that self-assurance are starting to appear, even if they sometimes aren’t apparent when reading a linescore. Within each one of Imai’s starts are moments that seem minuscule to some, but they are seminal to him while searching for stability. Sometimes one arrives before even coming set.

“Before I even throw the baseball,” Imai said through an interpreter. “For me, I have to put my body weight on my left heel. I was struggling before. But for today’s outing, I was able to do it most of the time and being comfortable enabled me to attack the zone.”

Doing so spearheaded the most encouraging outing of Imai’s erratic season. Yes, he started a combined no-hitter six days ago, but what unfolded on Sunday afternoon at Daikin Park felt far more impressive.

Imai muzzled the first-place Milwaukee Brewers while trading zeroes with one of Major League Baseball’s most promising pitchers, two outcomes that seemed almost impossible when this month began. Imai had a 9.24 ERA then. Now, it is 5.52 — not near what should be expected from someone making $18 million, but meaningful progress nonetheless.

“There’s more confidence,” Astros manager Joe Espada said. “There’s a different presence about him when he knows, ‘OK, things are starting to go my way.’ That’s very important for him, just where he started and where he’s at now.”

On Sunday, Imai arrived at a corner the Astros were waiting for him to reach. That they languished against Milwaukee ace Jacob Misiorowski and lost 2-0 did not obscure a more meaningful development: Imai appears to have turned it.

Save one elevated slider, Imai matched Misiorowski across six impressive innings. Imai threw more pitches in a game than all but two major-league starters this season (Taj Bradley threw 114 on April 29, and Parker Messick tossed 112 on April 16). He got stronger as his pitch count rose, pairing effectiveness and endurance unseen in his previous six starts.

“He came in (after the sixth), and he was like, ‘I got more in there, I can go back out there for another inning,’” Espada said with a smile. “I’m like, ‘Well, I’m sure you can.’”

Espada did not allow it, limiting Imai to 110 pitches. He threw 59 percent of them for strikes, stockpiled seven ground-ball outs and surrendered just an 88.9 mph average exit velocity.

Just six of Milwaukee’s 16 balls in play against Imai were hit 95 mph or harder, progress for a pitcher who awoke on Sunday with a 50.8 percent hard-hit rate.

Neither Jackson Chourio nor William Contreras started for the Brewers, but that meant six left-handed hitters dotted their lineup. Imai entered allowing an .856 OPS against them. Fourteen of Imai’s first 18 walks this season came against left-handed hitters.

On Sunday, Imai limited Milwaukee’s lefties to a 2-for-13 showing. The most feared among them, former National League MVP Christian Yelich, took some silly-looking swings during his two strikeouts against Imai.

Only one of them worked a walk, a byproduct of Imai’s improved fastball command and the ensuing confidence to throw the pitch near the zone. Balancing the weight on his left heel helped. So did seeing better results in his past two starts.

“Right before I even throw, I’m more confident and settled in with my position,” Imai said. “So even before I throw, I’m more confident I can throw in the zone with high intent.”

Left-handed hitting Jake Bauers lined a two-run home run off Imai, but the 347-foot fly ball landed five rows into the Crawford Boxes. According to Baseball Savant, it would’ve been a home run in just six other ballparks.

Imai allowed just one baserunner after Bauers’ fourth-inning home run. The fifth and sixth frames also featured something new: an uptick in fastball velocity that Imai teased in spring training, but never had a chance to show in his first six starts.

“I was able to find a position where I’m really comfortable,” Imai said. “Even with high intent, I was very confident with being able to put it in the zone. I was very happy about that.”

Before Sunday, Imai had thrown just 28 pitches this season 96.3 mph or harder. His final 12 fastballs against Milwaukee all reached that threshold. Imai’s 106th pitch matched his hardest as a major-leaguer: a 97.6 mph four-seamer that Bauers spoiled foul.

“The coaches knew that I had more in the tank even after 100 pitches,” Imai said.

Well, now they do.