Johnson said he offered the Nittany Lions words of encouragement before Saturday's game.
"We don't want these guys thinking. We want them to go play."
"You can argue you spend more time with your staff than your wife at home."
Collins played for Penn State from 1991-94, leading the team to an undefeated 1994 season.
Warren's announcement came after fellow tight end Theo Johnson announced his declaration for the NFL Draft.
Fashanu is a widely projected top-five pick.