Madison, Wi (WSAU) Running back Zach Brown has been ruled out of tomorrow's Wisconsin homecoming game against Iowa. Coach Bret Bielema said the junior starter had a pretty significant concussion last Saturday at Ohio State. He has not practiced all week. Sophomore John Clay will start at tailback, with freshman Montee Ball and Erik Smith as the back-ups in that order. Iowa comes in with a 10 game winning streak, 2-0 in conference play.