I've seen a few posts recently about WM leading the league (or at least being high in the rankings) for zero and negative rushes. Is this a concern?
Sure, it'd be a concern if he were falling down, tripping over yardlines, bumping into the QB ...
But Barry Sanders consistently lead the league in negative rushes -- we all know how that turned out. He did so because he was always behind a struggling line, but he always was near the top of the league at the end of the year and always had a high per carry average.
Willis will be the same except the line in Buffalo is improving. The holes will open. And even though WM will still get dropped behind the line a bit, that's because he's taking chances and will be busting the 15-50 yarders with some regularity.