The Indianapolis Colts have placed starting safety Julian Blackmon on injured reserve due to a shoulder injury he sustained in Sunday's game against the Atlanta Falcons. Blackmon will miss the rest of the season, ending a strong campaign where he recorded four interceptions and 88 tackles. With Blackmon out, second-year player Nick Cross will take over as the permanent starter. The Colts also signed safety Henry Black from the Pittsburgh Steelers practice squad to fill the open roster spot.