McGee's running style is more like Rawls than probably any other back on the roster. There are times when he stops his leg drive when he gets hit like Collins does, but most often he's got quite a bit of leg drive and is more along the lines of Rawls to knock off his center.
I went back and looked at his runs vs the 9ers and I think you could see why they gave him some runs near the end in a side by side with Collins (speculation). At any rate, they wanted to see what he looked like live and that's what they got.