HOUSTON — Coach Bill O’Brien said he’s not going to announce who’s starting at quarterback against the Baltimore Ravens on Sunday, but it’s expected to be Case Keenum, who was signed off St. Louis’ practice squad on Monday.

Thad Lewis would be the backup. The Texans signed Ricky Stanzi for the practice squad.

Ryan Fitzpatrick (fractured tibia) joined Ryan Mallett (torn pectoral muscle) on injured reserve. Tom Savage (hyperextended knee) is out, too.

Keenum spent more than five months working with O’Brien and quarterbacks coach George Godsey before being waived on Aug. 31 to make room for Ryan Mallett.

“It feels great to be back,” Keenum said. “It means a lot. This is home for me. I’m very thankful for the opportunity the Rams gave me, and I learned a lot. It’s a great organization, but I’m very excited to be back. I was glad to get here and get to work.”

Keenum was 0-8 as a starter last season, but in his first three starts, he threw seven touchdown passes and no interceptions. They lost by one at Kansas City, by three to Indianapolis and by three at Arizona.

“He’s a hard competitor, and he’s going to give us his all,” said DeAndre Hopkins, the team’s leading receiver who was a rookie last season. “He does a lot of things well, and he’s an intelligent guy.

“It makes it easier that he’s been in this program, and he remembers this offense a little. I’m not sure how much, but it helps.”