He never had a comittable offer. At the time Michigan had a number of backs ahead of him (Brennan Clay, Austin White, etc). Michigan knew he'd accept an offer on the spot, so they were slow playing him until they knew what the others above him were doing (assuming they would have ever offered). He only had MAC offers going into the summer of his senior year, when MSU offered, he accepted shortly after.
I did not make this headline up