Vick Ballard was one of the more surprising rookie running backs last year rushing for 814 yards and helping Andrew Luck keep the Colts offense balanced enough to earn a playoff spot. Colts coach Chuck Pagano said Friday that Ballard had a suffered an ACL tear at practice Thursday after he planted his foot on the ground and his knee simply gave out. Ballard was the team's starting running back ahead of former Giants starter Ahmad Bradshaw and Donald Brown so it appears as though Ballard's carries will transfer over to that duo.