DENVER — Imaging on Houston Astros ace Hunter Brown’s injured right shoulder revealed a Grade 2 muscle strain, a diagnosis general manager Dana Brown described as “good news.”

“I would characterize that as positive — that it was strictly muscle and no issues with any of the bones or structures that you cringe to hear about,” Dana Brown said Tuesday. “The fact that it’s muscular, it’s a good thing.”

Neither Dana Brown nor manager Joe Espada specified which muscle is strained or offered a concrete timetable for a possible return. Grade 2 strains do involve partial muscle tears, according to the Cleveland Clinic. Espada said the righty will not throw for at least two weeks, after which he will be re-evaluated to determine the next steps in his recovery.

Hunter Brown, who is on the injured list for the first time in his major-league career, felt discomfort during a throwing session last week. He traveled back to Houston last weekend to be evaluated by team doctors. Espada said he spoke with Brown on Tuesday afternoon and that he “sounded well.”

“The fact that it’s muscular and there’s no damage to anything in there, it’s good news,” Espada said. “But the fact that we’re going to miss him for a bit just sucks.”

Espada said Brown did not complain of any discomfort before he “didn’t feel right” while playing a game of catch last week. Brown made his first two starts of the season without any issues, though his workload during both outings now could merit more scrutiny.

Brown threw 102 pitches during his first start against the Los Angeles Angels — more than any Opening Day starter in the sport. Asked Tuesday whether he was OK with such a heavy workload, Dana Brown devoted much of his answer to spring training outings he found surprising.

“I just found it fascinating that he was 96-98 (mph) in spring training,” said Dana Brown, who expressed skepticism this winter about any of the organization’s pitchers participating in the World Baseball Classic.

None of them did, but a league source indicated that Team USA inquired about Hunter Brown’s availability. He remained in spring training with the Astros.

“I would have liked to see a little slower buildup,” Dana Brown said. “He was fired up. I would attribute it more to maybe throwing too hard too soon. That’s always a concern. You don’t want guys gunning it the first few weeks of them getting built up. He was literally 97-98 (mph) often in all of his games that he pitched. I’d have liked to see him dial it back — maybe 95-96, touching, feeling a little bit. That’s the only thing.”

Brown later said, “I don’t think it’s one thing you can point to,” while reminding two reporters that Hunter Brown “came out and actually pitched better in his second start.”

Hunter Brown threw six innings of one-run ball against the Boston Red Sox. He did so on four days of rest, which he did only five times last season. The team yanked Brown after six innings and 78 pitches, in part due to his inflated workload on Opening Day.

Brown threw a career-high 185 1/3 innings last season en route to a third-place finish in American League Cy Young Award voting.

This year, much of Houston’s postseason hopes hinged on Brown’s assuming the mantle as the club’s unquestioned ace following Framber Valdez’s departure to the Detroit Tigers. Instead, the Astros must adjust without him for an indefinite period. The team added six pitchers this winter — four of whom are starters — in preparation for Valdez’s departure.

Still, Houston’s rotation awoke Tuesday with a 5.06 ERA — the fifth highest in the sport — and a league-leading 33 walks across 53 1/3 innings. Without Brown, pressure will shift to Cristian Javier, Lance McCullers Jr. and Tatsuya Imai — three men making a combined $47.8 million this season — to deliver for the duration of his absence.

Even without Brown, the Astros will still deploy a six-man rotation following Thursday’s off day. In all likelihood, they will summon Spencer Arrighetti from Triple-A Sugar Land to fill one of the two open spots.

Arrighetti is listed as Sugar Land’s starting pitcher for Thursday’s game, making him making him a logical candidate to start in the team’s upcoming series against the Seattle Mariners at T-Mobile Park. Other than to reiterate the plan to expand the rotation, Espada declined to share specifics of the next steps.

Peter Lambert, Colton Gordon and Jason Alexander could be called upon to help fill the other open rotation spot. Houston also has a cadre of long relievers — AJ Blubaugh, Kai-Wei Teng, Ryan Weiss and Cody Bolton — with whom it could cobble together bullpen games every sixth day. Bolton and Weiss performed a piggyback start during Monday’s 9-7 loss at Coors Field, a game Brown was originally scheduled to start.

Now, he must watch as Houston’s reinforced pitching staff tries to compensate for the glaring void he leaves.

“We are in a much better place,” Espada said, “but it’s impossible to replace someone like Hunter.”