Carter was injured and didn't play the second half against Boise State.
Notre Dame's run defense is among the nation's best.
Allar has thrown for 298 yards and three touchdowns through the first two games of the playoffs.
All but one staffer picked Penn State to win.
The Orange Bowl matchup marks the 20th meeting between the two teams and the first since 2007.
Nick Singleton and Kaytron Allen will arguably be Notre Dame's biggest challenge yet.