I posted this elsewhere yesterday (on Hawkblogger, prior to the info about Turbin's ankle) when the question was if Fred Jackson is signed, who leaves, Michael or Turbin? My thoughts were that Michael hasn't progressed nearly enough to be an NFL running back.
"It's a bit nit-picky, but even Michael's long run showed he still doesn't carry the ball properly - it was in his right arm the whole way down the left side, where it's easier for the defense to strip it and he can't use a stiff-arm to protect himself. Given his issues hanging on to the ball, the fact that he still, after all this time, can't figure out how to hold the ball tells us he isn't mentally prepared to be an NFL running back. He's had more than enough time to learn (but hasn't) the lesson Marshawn did - point A to point B do it Cable's way; after point B you can do your thing. He still is going from A to B via C, D and E, oopsie, 3 yard loss.
I think a team that uses power blocking rather than zone might be interested in him, though. There's no denying the physical ability, and having a different scheme may convince another team they can "fix" him."
Turbin's ankle injury throws the backup RB position deck of cards up in the air. The severity (or lack of it) will determine Michael's path. I think if Fred Jackson gets signed, then Michael is the odd man out once Turbo is healthy. He hasn't done enough on the field to beat out Turbo to this point and deosn't seem likely to do so.