SB Nation's Bill Connelly sent out a sneak peek of his updated S&P+ rankings, which are derived from play-by-play data and adjust for opponents, and Michigan is No. 3 (!!) in the nation. Yes, this seems too high and doesn't match the eye test given Michigan's offensive struggles. But the defense has been so dominant that Michigan's yard-per-play advantage has been significant. And, with how Michigan's previous opponents have performed this season, this doesn't seem *that* ludicrous.
Here are the full S&P+ rankings.