Let us assume that we retain coach Rodriguez. Most of the fanbase assumes that Gerg won't be. At the very least there will likely be two or three defensive coaches let go.
Candidates for the defensive coordinator position might include:
Bruce Tall: I assume this is unlikely. The defense has been poor enough that it would be hard to justify elevatingthe best position coach on what seems to be a weak staff. On the other hand if rodriguez is going to want his dc to play a 335 regardless of experience with it, Tall is probably better suited to do that than gerg. It would be hard to be worse. Ultimately, I believe that Brandon will want someone with a proven record and more appealing to the masses. So should rodriguez--he may only have one more year to prove himself.
Chuck Heater: If he's available this would seem to be a good fit. Michigan ties. Florida plays a tough style of defense which we expect to play. The fans for mchigan would embrace him because he played here and has had good success in the ESS-EEE-SEE. The DC job for heater would be an upgrade for him and could be a stepping stone to a head coach consideration here or elsewhere depending on how thngs go.
Randy Shannon: Probably a pipe dream since he will likely have a shot at a head coach position for a lower level major cnference school like Minnesota, Mississippi State, Maryland. It's likely he would choose that option if available. He'd be a good fit though. We already focus heavily on recruiting Florida and his ties there would further that connection. He's also the type of coach who could be hired and paid well and allow Rodriguez to continue to be very hands off with the defense. From the little I have read, Shannon places significant effort on kids going to class and staying out of trouble and would be a good fit with Rodriguez from that perspective. With his defensive track record Brandon would approve and likely be willing to pay. He's recently mentioned that the coach here is gven a lot and a lot is expected. This would certainly fit hat description and potentially se up a solid defensive staff for a couple of years unless or until Shannon were offered a good head coachng position or Rodriguez let go. if we,re willing to pay LSU type assistant money there could be a chance toland him. Detractors would correctly say that he doesn't have Michigan or Big 10 experience, but his track record would appease most fans (at least for a year or two).
Jim Herman: doubtful. He'd be an improvement over what we have. He's familar with the program. That however may actually be a reason he wouldn't be cnsided. RR has spent a signifcant amount of effort and time changing the way thngs were done before him. RR would likely feel threatened by that move and it's probably an impossibility for that reason.
My choice would be Shannon. I doubt he'll be available. I'd take Heater. Either would appease the alums and donors for a year or two. By then well know if Rodriguez is the guy.