BOISE, Idaho -- Boise State coach Chris Petersen says running back Malcolm Johnson will miss the entire season after tearing an ACL during no-contact drills.

Johnson was having a strong fall camp and was poised to be the No. 3 running back for the Broncos, behind Doug Martin and D.J. Harper. Johnson, who returned to the team after being declared academically ineligible last year, also was expected to play a big role on special teams.

Petersen says the injury is the only significant injury setback as the No. 5 Broncos prepare for Saturday's season opener against No. 19 Georgia.

Petersen says it's disappointing because Johnson returned to campus in great shape and with a great attitude.

The loss could open the door for more playing time for freshman Jay Ajayi.