Ohio State star safety Caleb Downs gave his reaction on Monday to the departure of defensive coordinator Jim Knowles, who left for Penn State.

However, Knowles wasn’t in attendance. About an hour later, reports surfaced that Knowles is leaving Ohio State to serve as Penn State’s next defensive coordinator. The move leaves Day searching for a replacement. Here’s who he might consider as he enters his seventh season as the Buckeyes' head coach.