INDIANAPOLIS -- The depth on the Indianapolis Colts' offensive line has taken a hit.

Guard Hugh Thornton will be "week-to-week" with a knee injury, coach Chuck Pagano said Thursday. The injury occurred during practice Wednesday.

The Colts waived guard Ben Heenan after reaching an injury settlement with him this month, and now Thornton is out.

The injury is another setback for Thornton, the Colts' third-round pick in 2013. He started 20 games the past two seasons only to lose his job to Lance Louis during the offseason.

Joe Reitz and David Arkin are the primary backups for Louis at guard. Donald Thomas, who was brought in to start at guard in 2013, is still on the physically unable to perform list and there hasn’t been a timetable set on when he will join his teammates in practice.

A possibility, albeit a long shot at this point, if truly necessary is to move Jack Mewhort from right tackle back to guard, where he started 13 games last season a rookie. They could slide Reitz into the starting lineup at right tackle.

The Colts would rather avoid something like that, because Mewhort has taken every snap at right tackle since the start of offseason workouts in April.