Coach Scott Frost said junior inside linebacker Will Honas will miss the rest of the season after suffering some knee ligament damage in Saturday's 42-28 loss to Purdue.
Honas was injured during the second quarter on a goal-line play. He was seen favoring his left knee.
The 5-foot-11, 200-pound linebacker will be able to redshirt, saving him two seasons of eligibility.
Honas has 15 tackles and has appeared in all four games. He stepped into a big spot against Troy when Mo Barry was ejected in the first half for targeting. He was on the field, alongside Barry, for many plays against the Boilermakers.