Petrino brought Louisville to relevancy 03-07, as well as a Heisman Trophy winner a couple seasons ago. That's a HUGE deal for a coach. Lamar left for the NFL, and it's one bad year.
Believe it or not, he has a lot of goodwill built up in Louisville, regardless of his checkered past. That "past" happened between his stints at UoL. He's been wildly successful as the Cards coach given their weak history. This will be the first season with less than 8 wins in 9 seasons total. (9, 11, 9, 12, 9, 8, 9, 8)
I'd wager that until he has around three seasons like this year, he isn't going anywhere.
edit; However, I also agree with what JohnnyDoe said. I'd almost like to see Petrino get fired this season bc I HIGHLY doubt Brohm would jump ship so quickly. I just don't think it will happen just yet (Petrino being fired). It would be nice to see them have to get a new coach, then we don't have to deal with it for about 5 years.
I still don't see CJB ever going there. Either he'll stay with PUR for a long time, or go NFL or Blue Chip (USC, LSU, TENN, FSU type). Not to cesspool UoL.