One article I read indicated there was some pressure on the part of Utah to have him step down because they were afraid their 'coach in waiting' would leave then Whittingham would inevitably retire in a year or two and Utah would suffer as a result.So he quits coaching then 2 weeks later he's back?
Honestly, I think Michigan has a lot to clean up and hiring Whittingham won't suddenly fix their mess. That mess might end up swallowing Whittingham.
Whittingham also has something like 11 grandkids in Utah. My prediction is that after 2-3 years, the pull of his family in Utah (as well as the yearn for the wide open spaces of the West) will have him wanting to retire for real.