Several reports/rumors have come out stating that he's having second thoughts. Who really knows - not much has been said since his November interview. With the season officially over, Wannstedt is probably checking into his draft stock as much as he can to offer the most information he can, while trying to get publicity for his seniors.
If he's back, I believe the football team would probably be ranked somewhere between #10 and #20. If not, maybe around #20 - #25.
Reports I've seen seem to place him as one of the top handful of running backs available, suggesting he could be a 1st or 2nd round draft pick. If he seems to be a lock for a 1st round pick, it would be hard to see him back. But it looks as if he really enjoys college life and Pittsburgh in general. Plus, I think he would love to get Pitt to a BCS bowl and really cement his legacy here. If he's back, Pitt will in all likelihood do what it can to promote him early on for the Heisman.