Posted by ESPN.com's Bill Williamson
The Chargers made a roster move Saturday by signing defensive end Keith Grennan to the active roster. He was on the practice squad all of this season and he was on the San Diego practice squad last season.
To make room for Grennan, safety Tra Battle was released.
Grennan was likely promoted because the Chargers will need him Sunday night against visiting Indianapolis because standout Luis Castillo will likely not play. He didn't practice all week because of a groin injury he suffered at Pittsburgh last Sunday.