The Colts have placed running back Vick Ballard on injured reserve and have promoted rookie tailback Kerwynn Williams from the practice squad to replace him.
The roster move was disclosed in the NFL’s Friday transactions.
The Colts’ starting tailback, Ballard suffered a torn anterior cruciate ligament in a practice drill on Thursday.
The 5-foot-8, 195-pound Williams led the Colts in rushing in the preseason, gaining 169 yards on 41 carries. He was one of the Colts’ two seventh-round picks in April. Williams, 22, played at Utah State, rushing for 2,515 yards for the Aggies.
Williams is listed as the Colts’ third-string running back behind veterans Ahmad Bradshaw and Donald Brown.