Ajayi, a redshirt junior, will be forgoing his final year of eligibility.
Ajayi has run for 1,689 yards on 325 carries this season for the Broncos. He finished first in the Mountain West Conference in the regular season with 25 rushing touchdowns and was second in rushing yards.
From NBC Sports:
Ajayi informed his teammates while in the huddle for the final rep in practice on Sunday. He reportedly made his decision to enter the NFL Draft without hearing from the NFL advisory group in place to assist with the decision-making [process] for underclassmen thinking about leaving for the NFL Draft.
Boise State head coach Bryan Harsin told ESPN.com, "I knew it was coming. And so did he because of the type of season he's had. There's no doubt in my mind he's a professional running back."
Ajayi's final game for Boise State (11-2) will be against Arizona (10-3) in the Fiesta Bowl on Dec. 31.
- Sarah Barshop