The 49ers are dealing with injuries in the secondary.
Ryan Barker's game-winning kick marked the first time since 2014 that Penn State has won on a walk-off field goal.
"Some things aren't going to go your way, but it's just how you bounce back for them."
Johnson was previously committed to Louisville.
Warren was also named Big Ten Offensive Player of the Week and AP Player of the Week for his performance against the Trojans.
