The people that beleive a back up QB is a waste of roster space need to look at history instead of fantasy football. Where not every team made it to the Superbowl a back up kept the team moving forward to get to the playoffs. Yates in Houston a recent example. Reich in Buffalo, Morral and Strock in Miami, Young in S.F. then Garcia, Pittsburgh has used a good back up a few times to keep things rolling, Dallas always has depth, why they wanted Kitna. Kreig in Detroit. The example of New York with the Hoss, Pats had Cassel and Brady as a depth QB for Bledsoe, of and Kubiak backing up Elway. Doesn't matter where they were taken in the draft, just matters they can play. Shit by English' standards Johnny Unitas would have never been on the playing field as well.
Don't give me the old school versus modern era stuff either, you had to be a lot tougher and a more rounded player back then, less roster size, less rules to protect players.
You have a limited window, poo pooing a back up QB that can keep you winning isn't sound judgement, we especially since we do not live and die by the pass. But you have to have someone that gets respect of the defense. Nobody respected TJacks ability to read the field is an example.