I think the divide is really the question as in which team has the greatest dropoff from starter to backup, I don't think there was a dropoff from Vick to Foles and I'd think if Vick comes back he will face a cacophony ( my verbal dynamics word of the day
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) of boos unless he absolutely shines.
The greatest divide of which I am aware is from PManning to Osweiler, unless his accuracy has improved the Broncos season is as over as bell bottoms if their starter goes down.
I think the guy you have as your backup and what you need from him is satisfied by KC in every expect-able capacity(yesterdays "word") if he was physically much better he'd BE a starter somewhere and his knowledge of the playbook and his OC's knowledge of what to expect from him is about as good a situation as you could hope for, add to that his ability to actually help teach the system to your starter ,JMO we would be foolish to try to replace him unless we had a damned good alternative and thought Sam was so accomplished in the system that he couldn't learn anything from KC.
I agree completely with deiter 'bout this ,I wouldn't mind if we got an athlete around the third round to develop and even as someone who came in and looked awesome with a veteran team in the rare appearance , became trade bait like we see from time to time in the league.