Yes, I only said "slow down" for a reason. I don't think he can be stopped. I think the most difficult thing to game plan against in football is a scrambling quarterback. You can devise ways to take away pet plays or to take away a stud running back. You can figure out how to bottle up a top receiving threat or to take away a teams blitz, but stopping a scrambler from running wild is tough.
Think about it, a scrambling QB does the majority of his damage when a play breaks down. At that point there's no accounting for where a defense ends up, and when he takes off running his athleticism takes over. Do you put a spy on Michael Vick and take a defender away from their pass coverage responsibility? You could, but any offensive coach will trust his guy (especially if his guy is as quick and shifty as Vick) to make a move and beat a defender one on one.
I don't think the Bears will alter their their defensive approach much to account for Vick. Other than practicing against a scout team QB that will take off (Does Caleb Hanie get that gig?), and of course pounding into their heads to be fundamentally sound in their play this Sunday.
I highly doubt the Bears will spy Vick. With the overall speed of their linebackers and their defense in general, it makes no sense to devote Brian Urlacher or any other player exclusively to Vick. Expect a lot of zone coverages this week with the under part of the zone looking to rally to Vick if he takes off. As a lefty, Vick is more comfortable throwing down field when running to his left, so if he's scrambling left the Bears have to maintain their zone depth a little longer but they can still squeeze to the sidelines. Also on those left scrambles Vick will look deep. The safeties can't get caught sneaking up to early on the threat of a run, stay deeper than the deepest until Vick crosses the line of scrimmage or chance getting burned by his big time arm.
If he's running right, as pointed out by Cris Collinsworth on Sunday Night Football, he's more prone to tuck it and run. The backside of the zone when Vick is scrambling to his right has to squeeze into the middle allowing the middle to attack Vick. If Vick completes a throw back to the left across his body the Bears will live with it.
So why zone as opposed to man to man? Two reasons, the most important being that zone is what the Bears do best. Tampa 2, Cover 3, and the occasional Cover 4 (or quarters coverage) mixed in will hopefully confuse Vick. The underneath zone will set the depth of their zone based on the drop the QB takes, thus all eyes are usually on the QB. And if all eyes are forward they'll see Vick scramble and they'll be quicker coming up to punish him. The second reason is that you don't want your defenders chasing receivers with their backs to the line of scrimmage, because that's when a scramble will kill you.
The Bears front 4 have been much better this season at generating pressure, and coming off a 6 sack performance, they hope to be hitting their stride. Whoever is taking the outside rush this week has to be cognizant of containing Vick. It'll either be the defensive ends or someone blitzing off the edge, as I wouldn't expect too many DT/DE twists this week. You'd rather not put your DT's in a position to have to contain.
Going straight at Michael Vick when rushing off the edge isn't going to work, the Bears have to rush him while being mindful of where the help is. In a straight 4 man rush the defensive ends (if they have a shot at a sack) have to attack the deepest shoulder in his drop.
For example, if Julius Peppers is rushing from the defense's left DE position (lefty Vick's blindside) and he has Vick in his sights for a sack, he has to attack his left, or deepest, side. If Vick feels the pressure, he either has to step up in the pocket (in which case you hope there is pressure up the middle) or take off to to the offensive's left. Trying to spin back to his right and he'll end up in Peppers' arms.
If there is any pressure at all, Vick is gonna make a move, you have to anticipate it and pursue accordingly. If the Bears bring a blitz up the gut, the DE's have to be aware that Vick will try and get outside the pocket and they must stay disciplined in their contain, even if it means not beating the offensive tackle. Box the corner and keep your outside shoulder free. If a LB or DB blitzes off the edge then the DE to the blitz's side can take a more direct approach or even make an inside move to get to the QB. But under no circumstances can the DE come with an inside move when there is no help to his outside.
I know we'd all like to see Vick take some big shots and be punished when he does run, but the Bears have to break down and make a sure tackle. Fundamentals. He has the quickness to make defenders miss, so if they get caught lining up for the knock out blow he could easily slip the tackle and pick up a few more yards.
One last aspect to slowing down Vick is the Bears offense controlling the clock and keeping him on the sideline. The last few weeks the Bears offense has done a good job sustaining drives, so I'd expect Mike Martz to keep up his commitment to the run game. Their offensive line is much improved so it does make sense to pound away a bit.
Vick will get his. He's that good. But the Bears need to stick to their game plan and not panic. Take their read steps, drop into position, contain on every play, and rally to him when he does take off.