According to the Sun-SEnt article, he can play all three spots. He was the MIKE at Buffalo and the Bills are going to go with Ragland who was injured last year at MLB. But... the article came from Omar. Take it for what is worth. Have to remember, even a blind squirrel can find a nut from time to time.
I read that Preston Brown was the Mike. Zach played WILL.
Buffalo runs a 3-4, there is no Mike.