I don't get Ruiz's departure, but so it goes. Supposedly Spanellis had already been passed by the freshmen who were redshirting this year, which explains his departure. Time will tell on that, but they were all highly rated, though that means less for OL than any other position, to be sure.
I would be surprised by any other departures amongst starters or significant contributors. Even Collins and Peoples-Jones will apparently return at receiver.
At this point it would definitely be a plus to get a proven grad-transfer for the OL, but I have bigger concerns for DL and CB/NB, where they're apparently looking at grad-transfer options. Even so, I expect the defense to be pretty good, regardless, as it has been the past 5 years.
Otherwise, Michigan under Harbaugh has proven that they'll beat everyone except Ohio State at home and beat anyone else outside the top 25 anywhere, so 10-2 is a reasonable early prediction (@Minnesota being the most likely second loss)..... Washington in Seattle will be dangerous, too, of course, but they'll also have a new starting QB and other new starters in addition to replacing Peterson (though I realize they'll return most of their assistants by promoting Lake to HC).