Variety. He hasn’t been very successful when they just run him into the middle of the line, and while his most successful runs seem to be to the outside, most teams have been able to key in on him in the obvious situations. In order to really get him going, they need to continue to mix him in on both the outside and inside, because eventually the defense is going to be caught flat-footed and anticipating the wrong thing for just half a second too long.
But variety in his personal game isn’t quite enough. Khalil Herbert is a fabulous change-of-pace back (although the split seems to be pretty equal for the most part) that gives a completely different look to the defense.