Knowles would join James Franklin's Penn State staff after three seasons at Ohio State, where he won a national championship.

Penn State announced Monday it had hired Jim Knowles as its defensive coordinator. According to multiple reports, Knowles reached a three-year contract with an average annual salary of $3.1 million. Knowles is a Philadelphia native. In a statement, Knowles said he was "excited for this opportunity" to join the Nittany Lions' program.

As Ryan Day looks to hire his fourth defensive coordinator in seven seasons, here are potential candidates to replace Jim Knowles.