Belton was forced to miss last weeks game against Virginia after sustaining an ankle injury against Ohio in the season opener. He has since remained day-to-day. Day went on to start in Belton's place but ultimately suffered a shoulder injury during the course of the game. He is now listed as day-to-day, as well.
With both back's potentially unavailable against Navy, the team will operate under a running back by committee mentality.
"Those guys are day to day, so not sure if they're going to be able to play," O'Brien said of Belton and Day.
"It'll be [Curtis] Dukes," he said when addressing a potential starter. "You'll see [Zach] Zwinak in there, two big guys, and you may even see Michael Zordich do some things there."
Dukes rushed for 30 yards on 10 carries against Virginia while Zwinak registered three carries for two yards.