Absolutely. The Tuna disdains players who get injured that he can't count on. That's a big pet peeve of his. JJ has been hurt in both of his seasons in Big D. If he were to go down again (even if it was only for a game or two) and Barber stepped up (which would not surprise me one bit because he's talented) I think the Tuna would stick with him. The Tuna can be very unforgiving and once you get in his doghouse it can be very difficult to get out of it.
Its true he doesnt like players who get injured but as was shown last year, he will stick with JJ when he is healthy.
Barber does not get the tough yards and is too small for short yardage situations. He will never get his shot unless Jones gets a serious injury or leaves the team. Jones was injured and in the doghouse the last two years but Bill went back to him anyway and will again in the future. So the idea that Bill would stick with Barber instead of Jones when he is available just wont happen.