EVANSTON, Ill.(AP) Northwestern quarterback Mike Kafka injured his leg in the second quarter Saturday and had to leave the Wildcats' game with No. 12 Penn State.

Kafka was replaced by Dan Persa midway through the second quarter. After talking on the phone on the sideline, Kafka left for the locker room with just more than five minutes to go in the first half.

He had completed 14 of 18 passes for 128 yards and carried eight times for 42 yards, including a touchdown carry to help Northwestern build a 10-3 lead.