Even if he's lost a step, Vick throws the ball as well as ever. Talent has never been an issue - what he lacks is focus. Whenever Vick has his back to the wall, he's plays like an MVP. Vick was trying to redeem himself during the entire 2010 season and that motivation returns during every crucial game winning drive. Vick is a classic underachiever- he has all the potential in the world and says all the right things after he screws up.
For this reason, I say give Foles some snaps in practice to send a message. Get the kid ready to play and show Vick his contract doesn't guarantee the starting job. It won't rattle the team's confidence, it'll show them everyone will be held accountable for their play.
This alone should light a fire under Vick's ass and sharpen his concentration. Hopefully a greater sense of urgency will suffice in maintaining consistency. If Vick continues to struggle and turn the ball over, I say take the next step and bench him 2-3 series. If those series result in several touchdown drives, we have a QB controversy, otherwise, put Vick back in and hope it was enough to wake him up.
The merits of Vick vs Foles are another matter I'd also be happy to discuss, but this is really about getting Vick on track. Vick spent over a year in jail; he can be benched for poor performance without hurting his feelings. Maybe its just what he needs.