Right-handed reliever Jordan Jankowski will rejoin the Astros on Sunday from Triple-A two days after being optioned back to Fresno. Jankowski was sent to Triple-A Friday night before Dallas Keuchel was activated from the 10-day DL on Saturday morning.
Morton, who tossed seven innings (96 pitches) in his most recent start on Wednesday, pitched a full bullpen session on Friday and felt "OK" afterward, he said.
Saturday, in accordance with a starting pitcher's normal off-day routine, Morton played catch, and he reported an "abnormal" feeling to the Astros' training staff during Saturday's game against Baltimore.
"I just didn't feel right," Morton said. "Went and got checked out and it was a little more serious than we thought. It was just more severe than we thought. We don't know what's exactly going on in terms of degree of severity. … I just described to our trainer that there was just something abnormal. It was just precautionary to get it checked out, but turns out it was a little more serious."
Morton will not throw for at least one week -- and possibly longer -- and is expected to "definitely" miss multiple starts, Hinch said. Peacock, a comfortable substitute to Hinch, will join the Astros' starting rotation for now.
"It's very frustrating," said Morton, who had season-ending surgery on his torn left hamstring in 2016. "My work, hopes and goals [are] all [to] completely avoid injury. But reality sets in, and I've gotten to the point where I'm not even surprised by it. I just have to roll with the punches."
"We're fortunate we stretched him out a little bit last week," Hinch said of Peacock, who tossed 4 1/3 scoreless innings last week against the Tigers. "Obviously, we didn't want to lose Dallas, but Peacock got a ramp-up to being in the rotation now for the foreseeable future. He's been good. He's missed bats and really gotten off to an excellent start and an excellent start last time. If we can build on that momentum, it'll be nice to have him be able to step up."
Christian Boutwell is a reporter for MLB.com based in Houston. This story was not subject to the approval of Major League Baseball or its clubs.