You cannot ignore the contract that Pats* gave MG in this discussion. Bills tendered him at the exact replacement value, and so far they've been proven right.
Do you think NE is wise to allocate $4 million to what appears to be a one trick pony? He has 0 yards on 2 4th down carries, which was supposed to be his calling card. Pats* would have had better production for less $$ out of Blount. Do you find it odd that in an offense as varied as NE's, MG has not caught a single pass in 3 games?
You understate the Bills offensive additions to MG's career average. He's averaged +2 yds more per carry here. You'd figure that playing with Brady, he'd be well over 4.0. But just the fact that his numbers aren't that distinguishable from Tolbert's says a lot.