As important as it is to start the right guy, I would be a little concerned about Carnes garnering significant playing time and possibly scaring away Turner. Of course, you want guys to come in who aren't afraid of a little competition, but between the athletic abilities of Carnes and Green (especially if Carnes establishes himself as a young-gun starter) and their combined youth, Turner might look at a school with a little bit more oportunity for PT.
Carnes is here, Turner is still a hope. There's an entire calendar year between now and when he can commit (or half if he does come in at semester).
Also, if that is what would scare Turner away then we don't need that QB (not saying it is). I want a QB who looks at everyone present and says, "I'm still going to NU because I'm better than what they have" - that's when we'll get back to the top.
Carnes will get a look this year because of what's in front of him. Also, that has to have ran through Turner's mind - if Carnes sees PT as a frosh it's probably because the folks in front are pretty bad.
Move Cody to a different skill position and let him produce. I tanked fast on Cody because of his consistent inconsistency with regards to where the ball ended up.
He looked like an athlete throwing the ball. Vince, Terrel, Mike Vick never looked that far off in college....