Texans free safety Danieal Manning will miss at least four weeks after having surgery on his left fibula on Monday, coach Gary Kubiak said.
Manning fractured his fibula on Sunday at Tennessee while making a leaping interception in the second quarter. He was on crutches in the second half and after the game.
"We think there's an opportunity for him to come back this year," Kubiak said at his Monday press conference. "I think we're definitely talking about four weeks, somewhere four weeks and beyond, whatever that's going to be.
"We'd love to wait on Danieal. We'd love to get him back before this season's over, so we did the work today and then we'll see how the progression goes over the course of the next three weeks and see if that's going to be a possibility, but right now we think it is. That's good news."
Manning has helped the Texans' passing defense improve from 32nd in the NFL in 2010 to sixth this season. The sixth-year veteran has two interceptions and 32 tackles since signing from the Chicago Bears as a free agent. He also ranks sixth in the league with 27.4 yards per kickoff return.
Third-year safety Troy Nolan will take Manning's place in the starting lineup. Rookie Shiloh Keo, a fifth-round pick from Idaho, becomes the top backup to Nolan and strong safety Glover Quin. Kubiak said the Texans also could call up Torri Williams from the practice squad or use rookie cornerback Brandon Harris at safety.
Nolan has played in every game this season. A seventh-round pick in 2009, he had 10 interceptions in two years at Arizona State and three interceptions last season. Kubiak said he likes the progress Nolan has made under first-year Texans defensive backs coach Vance Joseph.
"He's always had a knack for the ball," Kubiak said. "When he's played, he's come up with interceptions and come up with big plays... The thing for Troy (has been) getting comfortable with the mental part of the game to where that was easy for him so that his talents could go take over. That's been something that we've been looking for. He played upwards of 30 snaps yesterday without any mistakes, and that's a very positive sign."
Harris, a second-round pick from Miami (Fla.), has played in only three games this season. He played primarily on special teams in those three games.
"We've been crowded at corner all year long from that standpoint, so that's made it tough on him," Kubiak said. "He hasn't done nothing wrong. He's done some good things… He's kind of caught in a battle with Brice (McCain) every week when we suit guys up as far as special teams goes.
"Bright player, understands schemes, understands what's going on, and (defensive coordinator) Wade (Phillips) and Vance think that we can catch him up real quick. We're going to take a look and give him an opportunity to do that and work with him over the course of this week."