Given that the competition in camp was so close and that Frank went to JD early well before Vick was hurt, my question would be does he automagically get his job back even when he is available? If JD is performing and DV is rusty, possibly gimpy, how can you pull JD to put Vick back in?
In the absence of another bad break (no pun intended), JD looks like the guy.
Based on how they have done it in the past, Vick would automatically get his job back, but for that to happen, he'd have to be fully healthy, and I'm not sure that will happen.
Getting the job back, and keeping it, are two different things, though. For him to keep it, he'd have to play at least as well as JD was playing. Let's suppose that JD was playing well, and Vick comes in and struggles. The formality that you can't lose your job by injury would not prevent them from putting JD back in.