Penn State defensive coordinator Tom Allen is leaving for Clemson. Here are potential candidates to replace him.

STATE COLLEGE, Pa. (AP) — Penn State has lured Tom Knowles away from Ohio State. The Nittany Lions hired Knowles on Monday to serve as their defensive coordinator. Knowles held the same position with the national champion Buckeyes for three years.

Penn State has been on the lookout for a new defensive coordinator for the past two weeks. That is how long ago Tom Allen decided to leave Penn State after one year to become the defensive coordinator at Clemson. So what exactly has been taking Penn State so long to name his replacement on James Franklin’s staff?