Michigan offensive coordinator and quarterbacks coach Kirk Campbell has a major overhaul on his hands after losing several starters from last year’s National Championship team. The Wolverines will need to replace several offensive linemen, running back Blake Corum, a few receivers … and, of course, projected first round quarterback draft pick J.J. McCarthy. That piece will be the biggest, as it is on any team. Veteran Davis Warren probably looked the bet Saturday, while Alex Orji also had his moments. “We wanted to be turnover free. We had the one [an interception [by Jayden Denegal], but then…