here's what i know about targeting after the last few years. The word Absolutely does not apply. Nobody knows exactly what it is. It seems about half the time the rules analyst disagrees with the refs on the field. I have seen targeting called without ducking the head, or helmet to helmet contact and maybe just a forearm that slightly contacts a facemask. I've also seen guys get laid out with direct hits to the head and no call. Then there's the aspect of being a "runner" or being "defenseless:. It's way too open ended,
Was the Michigan hit targeting? Maybe. Like i said, i've seen plays just like that called and not called so who knows. I don't think it should have been targeting. To me targeting should be when a defender goes helmet to helmet by choice. In other words, he chooses to hit high when he could have made the same tackle lower. This is why I feel that when a runner lowers his head or is diving or otherwise close to the ground, the defender should have the right to also go low to meet him and stop him.
In situations like that, there almost has to be helmet to helmet contact because the runner took away all other strike zones by going low. That's why targeting rarely applies to RBs running up the middle. It is acknowledged that the defender has to go low to meet a low RB. But for some reason, WRs are exempt. They expect defenders to suspend the laws of physics to tackle WRs.