It could be that he played because he was ready. At least he looked ready to me. Say what you want about Brooks, but I'd never describe him as fragile.
No. He played because he was ready. You said "He won't play. Bank on it", not 'he won't play unless they need him'.
He was ready, he needed to get some real game time before the B10 season hits us, and you were wrong. And you will be many times before this season is over. Book it.