It will have to be a player that works in the 50-100 markets and isn't already here. That does not leave many candidates.
Word has been getting around that Double O has had folks kick the tires, but has only had interest in 92.1 for stick value.
If you are an outside player, you'd want a cluster that is generating significant cashflow, which would leave the Inner City stations as your first choice.
At auction, I believe you will see the Inner City markets go to different parties, with SF and NYC going to operators looking to add an FM signal.