Posted by ESPN.com's Adam Rittenberg

Wisconsin junior running back Zach Brown is questionable for Saturday's game against Iowa (ESPN, noon ET) after sustaining a concussion at Ohio State.

Brown had only four rushing attempts for six yards against the Buckeyes. Badgers head coach Bret Bielema said if the team was practicing Monday, Brown wouldn't be able to go.

Freshman Montee Ball is listed as the backup to John Clay at running back on Wisconsin's depth chart.

Though Clay rushed for only 59 yards on 20 carries, he impressed Bielema and the other coaches after battling through an ankle injury.

"John in my mind took a huge step forward Saturday," Bielema told local reporters Monday. "I know statistically he wasn't where we need him to be. That was a very good defense we were going against. But John had to do a lot to get himself ready to play last week and he did it. The look in his eye and the way he approached things shows me he might be ready to take a big step forward as a player."