Because it is hard to double him when he is in the locker room getting an X-ray.
Well, that was kinda my point there. Once Pollard went out, Lamb was the only real threat for chunk yards. The fact that he was frequently running with a LB or running free was perplexing. Those TE's or Elliot may be able to pick up a first down, but Lamb was the only way Dallas was going to get a big play.
