Senior tackle Ray Willis (ankle), a three-year starter, will not start and may not play in the game after limited work this week.
Willis has been bothered by an ankle injury suffered in the regular-season finale against Florida.
David Overmyer, a redshirt freshman from Lilburn, Ga., will make his first career start in Willis' place. The Seminoles also could move sophomore Mario Henderson, who backs up senior All-American Alex Barron at the outside tackle position, in case of emergency.
Still, Castillo is expected to play in the game.
The status of cornerback Leroy Smith remains a question mark.
Smith had surgery on his knee and arm following the Florida game. Antonio Cromartie will start for Smith at cornerback.
The Seminoles are determined to end the season on a positive note.
"I think it would give us a good start for spring drills, going into next season," fullback B.J. Dean said.
"I want the season to end on a good note for the seniors as well. A lot of them are close friends and I don't want them to go out with a loss."