Without defensive coordinator Jim Knowles in attendance on a day sources told ESPN's Pete Thamel he was finalizing a deal to join Penn State, Ohio State celebrated its national championship with 30,000 Buckeyes fans on Sunday at Ohio Stadium in Columbus.

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.