I believe all of the current QBs on the roster are merely 'placeholders' until O'Brien finds his guy.
Maybe one of them steps up into the role, but I get the feeling that O'Brien is not going to go the desperation route of signing someone long term if the coach does not see him a a long term solution to QB.
I mean, c'mon, we all know how long McNair's leash can be with his head coaches. Dudes have to go 2-14 and have the bottom fall out to get fired, so O'Brien is not going to press it and try to fit a square peg into a round hole.
Prepare yourself for a minimal 4-5 year plan until O'Brien gets his pieces into place. He just has to field a competitive team that seems to be capable of greatness next season to qualify for Mr. McNair's almost infinite patience.
These are not meant to be disparaging remarks, btw, but rather analysis based on the history of this franchise and how the owner has tended to operate.
Patience, grasshoppers.