Harbaugh has not definitively ruled out going back to the NFL, and reports are that he will jump if an NFL job is offered. So far the Broncos and Colts are mentioned as the two most likely spots. My guess is that he ends up in Denver. The new ownership will be more than willing to pay him, and they won’t need to offer compensation like they would have to to New Orleans to get Sean Payton.
It all depends on how high the money piles are that he gets offered. His contract with Michigan runs for 4 more years. It’s for $7+ million per year plus incentives estimated at $2+ million for the last season.