Hagler, who was on the Colts roster from 2005, his rookie season, through last year, was brought in after weak-side starter Clint Session missed the past two games with a hamstring injury and his replacement, rookie Kavell Conner, had to undergo surgery after breaking a bone in his left foot in last weekend's 27-13 win at Denver.
"There is a possibility (he will play Sunday), there is no question about that. We'll have to do some catch-up work here in the next couple of days, but you could see him out there for certain."
The Colts drafted Hagler in the fifth round of the 2005 draft out of the University of Cincinnati. He spent his rookie season on the Physically Unable to Perform List but contributed afterward at linebacker and on special teams. He started 17 games at linebacker in 2007-09 -- the first seven games last season before he sustained a season-ending torn bicep.
"That confidence is there," he said. "As long as I'm on the field, I can play. I just have to get that opportunity."
The Colts also added fullback/tight end Matt Clapp and wide receiver Chris Brooks to their practice squad, the Indianapolis Star reported.