Nelson made an appearance in all 16 of Penn State's game in 2024.
Penn State dropped their second straight game.
The Nittany Lions have won three consecutive EIVA titles.
Clifford tallied 15 receptions for 266 yards and a touchdown last season as a redshirt junior.
The two signal callers played the majority of reps in Penn State's spring game as they vie for the backup quarterback job.
"There's an opportunity here to join the room and compete."