All I think is that Lacy has had injury problems throughout most of his college career, which has always gotten a lot of attention because Alabama relied heavily upon him after Ingram and then Richardson left. When Lacy was the #2 RB after Richardson he still ran for some 600+ yards.
When he was the #1 RB he more than doubled that and that was after the initial instance of the toe injury. The guy gets injured but keeps playing, there have been a lot of great NFL players that had that same demeanor.
As far as the Alabama Offensive line, analysts were not convinced of their invincibility at the beginning of the 2011 or 2012 seasons. It's a combination of both the line and the RBs that make Alabama what it is.
Lacy will play, and put the work in to succeed. He's already shown that otherwise he would have missed far more games in his college career than he actually did from all those "injuries".