Colts safety Robert Mathis is the latest member of the Colts to miss time due to injury this season.
The team announced Wednesday that Mathis will miss four games with a concussion.
Mathis, who has played in all 16 games this season, has not played since Week 9 after missing the last four games due to a torn ACL.
Mathi missed all of last season with a foot injury and is the fourth defensive back to miss a significant amount of time this season with injuries.
He has missed two games with an injury and missed the first three games with his knee injury.