Castonzo (ankle) announced his retirement Tuesday, Joel A. Erickson of The Indianapolis Star reports.
Castonzo (ankle) was placed on injured reserve Friday.
Head coach Frank Reich said Wednesday that Castonzo will undergo season-ending ankle surgery, Stephen Holder of The Athletic reports.
Castonzo (knee/ankle) has been ruled out ahead of Sunday afternoon's game against the Steelers.
Castonzo (knee/ankle) is questionable for the Colts' Week 16 matchup against the Steelers, Andrew Walker of the Colts' official site reports.
Castonzo (knee) is officially active for Sunday's game against the Texans.
Castonzo (knee) is active for Sunday's game at Las Vegas.
Castonzo (knee) is officially listed as questionable for Sunday's game against the Raiders, Andrew Walker of the Colts' official site reports.
Castonzo (knee) has been ruled out for Sunday's game at Houston, Kevin Bowen of 107.5 The Fan Indianapolis reports.
Castonzo (knee) sustained an MCL sprain and is expected to miss some time, Tom Pelissero of NFL Network reports.