Absent some unforeseeable 5-7 type season, he's fine. I think he needs at the minimum a CCG appearance (and at that point a win with the East being undefeated there) with OSU undergoing a coaching transition, PSU replacing the QB who saved Franklin's job, and MSU seemingly content to squander an elite defense by just rearranging the deck chairs on the Titanic offensively, to ward off a very, very uncomfortable offseason next year.
Honestly, I don't think that's necessarily true. It depends on who the losses are to. Looking at the schedule, this looks like another 10-2 kind of regular season. If the losses are to OSU and ND, Michigan could squeeze into the CCG, or they could miss it without much hand-wringing.
Now if one of the losses were to MSU (...) woof. Harbaugh would survive it; he wouldn't realistically even be at risk of getting fired by Warde for ... years, if ever (to be honest), but the town and media would become a
hellscape.
If Michigan wins 10 games and one of those wins is MSU, the spirit will be "not perfect but that's not bad." It's funny what that means for the rivalry. In 2007 and before, it had become a bit of an afterthought. I think MSU hadn't won consecutive games in 40 years and Lloyd Carr went 10-3, including that 6 game streak lasting through Dantonio's first year. MSU really deserves credit for resurrecting that. Dantonio's record is now 8-4, but there was a real feast between 2008 and 2014, 6-1. That was absolutely and bar-none the hardest thing Michigan fans had to stomach through Rodriguez and Hoke.
And it adds up to there being zero chance for the fanbase to stay sane if they lose that game. There really isn't any game on the schedule that has more outsized rage than versus MSU. Unfortunately, though winning that game is essential, winning it is also unlikely to tilt the scales much in the Big Ten East race, at least not as much as the OSU game can.