The Texans placed safety Dominique Barber on injured reserve on Thursday and claimed cornerback Jason Allen off waivers from the Miami Dolphins.
Allen (6-1, 200), a fifth-year pro, started the first seven games for the Dolphins this season and had three interceptions. A first-round draft pick out of Tennessee in 2006, he was waived after Miami signed cornerback Al Harris earlier this week.
With Allen as a starter, the Dolphins ranked 10th in the league in passing yards allowed per game. The Texans rank 32nd in the league in pass defense. Allen has more experience than every Texans cornerback except for sixth-year veteran Karl Paymah.
Barber was a key contributor on special teams and the backup to Bernard Pollard at strong safety. He had arthroscopic knee surgery on Thursday morning after he was injured during a special teams drill at Wednesday's practice.
"It's a tough guy to lose," Texans coach Gary Kubiak said Thursday morning. "He's been our most productive guy that's been on the field for us the most on special teams, and probably our most valuable player from that standpoint. So that's a big, big blow. We're going to have to have somebody step up this weekend, and we're going to have to decide who that's going to be."
With Barber out, Troy Nolan is the only backup safety on the Texans' roster. Before it was known that Barber would be out for the season, Kubiak said that practice squad safety Torri Williams could be an option to replace him.
"We'll have to see after the scope what type of time we're talking about, so I don't know about that yet," Kubiak said. "(In) the immediate situation, we've got to take somebody who's active and give them a chance to help us on gameday, so that's what we've got to do."
Also on Thursday, the Texans also signed center Cody Wallace to their practice squad after releasing center Brett Helms. Wallace (6-4, 300) is in his third season out of Texas A&M.