Castonzo retires after 10 seasons with Colts

Indianapolis Colts left tackle Anthony Castonzo announced his retirement Tuesday after 10 seasons with the franchise.

"Anthony was a pillar of this team for the last 10 seasons," general manager Chris Ballard said in a statement. "He played one of the toughest positions in the game at an extremely high level for a long time.

"Anthony was a veteran leader in our locker room and will be greatly missed. We're thankful for all of his contributions to the Horseshoe. We love AC and know he will thrive in the next stage of his life."

Castonzo suited up in 144 regular-season games and eight playoff contests, all with the Colts. Indianapolis drafted him 22nd overall out of Boston College in 2011, and he gradually developed into one of the NFL's most reliable blindside protectors.

The 32-year-old anchored a unit in Indianapolis that allowed the second-fewest sacks in the league this season, though he finished the campaign on the sideline with an ankle injury.

Castonzo contemplated retirement last year, but he ultimately signed a two-year, $33-million contract to return to the Colts. Indianapolis will get $16 million in cap space back following his retirement, according to Spotrac.

The Colts are coming off an 11-5 season, but they now face major question marks at left tackle and quarterback - where Philip Rivers and Jacoby Brissett own expiring contracts - heading into the offseason.