Um, not saying Keithen should start or anything, and I don't think anyone is.
But, for a #2 back, I don't see what is "not good" about an average of 7.5 yards per carry and zero fumbles. It's quite possible that I'm an idiot though, so please feel free to clear that up for me. Until that's clarified, I contend that the dude is a good change of pace and has been making some pretty good cuts.