I really don't think Detroit can be stopped when they run 4 wide and Kitna is on his game.
You can't really bring a blitz against him and you can't cover the WRs long enough to get to the QB.
No offense, but Kitna didn't get knocked out of the game playing patty-cake with his teammates. That Martz offense has a tendency to get QB's injured. You CAN blitz a Martz offense...just ask
Kurt Warner. The pass rush doesn't always have to get there...it just has to get close to disrupt a QB...especially when he's been getting his brains beat in the previous few weeks.All those hits Kitna is taking speak highly of his willingness to stand in and take the hit...but they add up. And if it keeps up he's going to start rushing his throws (= inaccuracy), rushing his reads (= int's) or he's going to get hit one too many times (= injury). He's human, not invincible.
This O-Line still has a long way to go. When they have an O-Line that can stop the blitz with no help from their backs or TE, then you can claim that they can't be blitzed. Until then, Kitna won't be able to take a beating like that every week and still produce like he's been doing.