Carr, Manziel has been working hard to become a pocket passer. He's tough for a guy his size. He rarely looks to run it when the play breaks down, instead he'll extend the play by avoiding linemen and running to the sidelines waiting for a WR to get open. He will *rarely* run it himself this season. He extends and passes to his 2nd and 3rd options in a way he never would have before.
But yes, he needs to work on it even more, or his stay in the NFL will be an injury ridden short one.