Mike Tanier has an excellent article over at Football Outsiders about all the various looks shown last Sunday by the Packer defense. Warning: very technical, with diagrams! 

I hadn't realized how much they had dropped into a 2-4-5 formation. LB Clay Matthews and LB Aaron Kampman were playing like down lineman. I had forgotten to discuss how they had used Matthews. He spent most of the game going against former Pro Bowl LT Orlando Pace. He managed to disrupt several running plays to the outside and abuse LG Frank Omiyale on the INT by DT Johnny Jolly.