No word was immediately available Saturday but Monday IU coach Kevin Wilson confirmed that Mullen had suffered an ACL tear in the Missouri game that would require surgery and bring an end his 2014 season.
In addition, Wilson said that sophomore linebacker Marcus Oliver suffered the same kind of knee injury and will also have to have surgery and would miss the rest of the season.
Wilson indicated that because the injuries came before the fourth game of the season that both players would be eligible for redshirt possibilities. Neither player has taken a redshirt to this point in his college career.
Mullen, from Fort Wayne, Ind., had contributed primarily on special teams in the first three games. He had three tackles in the first three games. Oliver, from Hamilton, Ohio, had played in some reserve defensive situations at linebacker. He had 10 tackles, including six solo tackles, in the first three games.