"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.
Hardy spent five years in Happy Valley.
Mercedes-Benz Stadium has a capacity of 71,000, but there will likely be more in the stadium on gameday.