According to Rick Neuheisel Coach Day has been seeking defensive guidance from former coach Greg Mattison
https://thespun.com/big-ten/ohio-state-buckeyes/longtime-coach-shares-wh...
If true, it makes sense. We were better under Mattison and he has been a coach forever with good defenses at different levels.
Also, this would not speak well for Kerry Coombs being the DC after this season.