It's a little bit of a concern that Ware needed the day off, but it will take more than a sore back to keep him out of a playoff game. Ware has already come back the week after being carted off the field with what appeared to be a serious neck injury. I'm sure Wade Phillips is simply trying to get Ware some rest so he can be at full strength against the Eagles. If Ware is limited at all in Saturday's game, Victor Butler would likely pick up the extra snaps.
Cowboys running back Marion Barber is also dealing with a bruised knee this week, but he's expected to be fine for Saturday's game.