Injuries have caused linebacker Tyjuan Hagler to miss 34 of 71 games over his 41/2 NFL seasons. He is about to miss nine more.

The Indianapolis Colts placed their starting strong-side linebacker on injured reserve Wednesday with a ruptured biceps muscle suffered Sunday against San Francisco. The season-ending injury was preliminarily diagnosed as an elbow problem.

The Colts activated rookie Cody Glenn from the practice squad to fill Hagler’s roster spot, and Hagler will be replaced in the starting lineup by Philip Wheeler or Ramon Humber when the Colts play Houston at Lucas Oil Stadium on Sunday.

Wheeler was a third-round draft pick in 2008. Humber is an undrafted rookie from North Dakota State. Neither has started a game, but both are core special teams players.

Wheeler had the starting strong-side spot during the preseason but was beaten out by Hagler. The Colts hope he’s ready.

“He has no choice,” Colts coach Jim Caldwell said. “Philip’s not a rookie. We’ve had rookies play for us at a number of different places that haven’t been here very long. He’s been here a couple years. We fully expect that if he’s in there, he’ll play well.”

Running back Donald Brown (shoulder) returned to practice Wednesday, but injured cornerbacks Kelvin Hayden (knee) and Marlin Jackson (knee) did not.

Hayden was injured Sunday. Jackson has missed the past three games but said Wednesday he will play against Houston, although no final determination will be made until later this week.

Hayden and Jackson would be missed if one or both are unable to play against quarterback Matt Schaub , wide receiver Andre Johnson and Houston’s third-ranked passing game.

So would safety Bob Sanders , who missed practice with a previously undisclosed elbow injury.

Colts wide receiver Anthony Gonzalez (knee) appears a lock to miss his seventh consecutive game.

“He’s just still trying to get to a point where he feels like he can function at his normal level, and he’s not there yet,” Caldwell said. "How long that takes him just depends.

“I know he’s taking a look at it, getting more opinions, things of that nature, and kind of moving forward.”

Stover makes adjustments

Kicker Matt Stover went 4-for-4 to help the Colts beat San Francisco 18-14 with field goals of 38, 33, 31 and 40 yards. His second kick almost brushed the left upright.

“I was very angry with that field goal,” he said. “I know I made it, but I know in the long run, you keep hitting it like that, you’re going to miss.”

Stover’s last two attempts were intentionally right of center.

“Over my few years of kicking, I’ve learned you have to adjust on the fly,” he said.

Stover is in his 19th season. He is filling in while Adam Vinatieri recovers from knee surgery.