If he were a 2014 kid, this would be really awful news this late in the game. But he's 2015. Plenty of time to identify other options or for him to come back around. Given Hoke's policy of "no visits" and Campbell's desire to look around, a decommitment was necessary. It certainly decreases the likelihood of us landing him, but I think a decommitment would be a far more damning development if we were like most schools that do allow verbal commits to look around.
Certainly respect his right to weigh all options before making his decision. Still would love to see him suit up at Michigan.