DENVER — Imaging on Houston Astros ace Hunter Brown’s injured right shoulder revealed a Grade 2 strain, the team announced on Tuesday.

Brown will “refrain from throwing for a few weeks,” according to the Astros, who offered no more concrete timeline for their ace’s return. Manager Joe Espada is expected to address the injury before Tuesday evening’s game against the Colorado Rockies. Grade 2 strains do involve partial tears of either muscles or ligaments, according to the Cleveland Clinic.

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.

The right-hander made his first two starts of the season without any issues, though his workload during both outings invited intrigue. Brown threw 102 pitches during his first start against the Los Angeles Angels — more than any Opening Day starter in the sport. He made his next start on four days of rest, which he only did 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 voting. This year, much of Houston’s postseason hopes hinged on Brown 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. Their rotation awoke Tuesday with a 5.06 ERA — the fifth-highest in the majors— and a league-leading 33 walks across 53 1/3 innings.

The team is planning to deploy a six-man rotation following Thursday’s off day and, in all likelihood, will summon Spencer Arrighetti from Triple-A Sugar Land to fill one of the two open spots.

Peter Lambert, Colton Gordon and Jason Alexander could be called upon to help fill the other. Houston also has a cadre of long relievers — AJ Blubaugh, Kai-Wei Teng, Ryan Weiss and Cody Bolton — with which it could cobble together bullpen games every sixth day.

Neither solution is encouraging, which puts pressure on Cristian Javier, Lance McCullers Jr. and Tatsuya Imai — three men making a combined $47.8 million this season — to deliver for however long Brown is out.