They have have to make a splash, so I could see them reaching out to Day, Riley, Kiffin, Harbaugh, maybe McVay if the Rams have a down year or the Vikings' O'Connell, if the Vikings continue their spiral and he's out of a job in December, i.e. big splash and not necessarily best coach.
Or . . .
With what they have to pay out, they probably just promote Petrino.
With all that being said, UK's Stoops would be a solid hire, and better than what they have now.