Allen had a career high in carries against the Hawkeyes.
Ethan Grunkemeyer will start in place of Drew Allar.
"We've been working on it. We're ready for it. I'm excited."
Grunkemeyer will make his first career start on Saturday against Iowa.
Penn State sits amongst the bottom four of the Big Ten standings after going 0-3 in its first three conference games.
Dom DeLuca recorded 12 tackles against UCLA in his first start of the season.