HOUSTON -- Aaron Sanchez, one of three players the Astros acquired from the Blue Jays in a July 31 trade for outfielder Derek Fisher, will miss the rest of the regular season. Astros manager AJ Hinch said Thursday the right-hander would go undergo shoulder surgery soon.

Sanchez, who threw the first six innings of a combined no-hitter in his first start in Houston on Aug. 3, was pulled after 2 1/3 innings in his last start Aug. 20 and said his pectoral muscle had been bothering him, even before he was traded. Hinch said he started to get concerned last week when Sanchez still wasn’t throwing.

It’s not clear what kind of surgery Sanchez will have or what his recovery will be.

“We may see him back here at some point in September just as a teammate,” Hinch said. “It’s a bummer for him. It’s tough for us. We expected him to contribute down the stretch and unfortunately he won’t be able to pitch.”

The Astros brought in Sanchez with hopes he would fill their fifth starter slot, and he posted a 4.82 ERA in four starts with the Astros. He was expected to compete for a bullpen spot in the playoffs. Lefty Framber Valdez has taken over as the Astros’ fifth starter behind American League ERA leaders Justin Verlander, Gerrit Cole and Wade Miley, and Zack Greinke, who was acquired the same day as Sanchez in a trade with Arizona.