Again, many times with defenses their stats depend on the offense. Stat-wise NO potent offense makes NO defense look better then it really is. All we have to do is look at Green Bays defense before Rodgers got hurt, compared to after he got hurt.
Packers Defense, Weeks 3-12
--------------------PPG------------- YPG ------------------RUSH YPG------------------- W-L
Weeks 3-8-------20.8----------- 280.4--------------------77.4---------------------------4-1
Weeks 9-12*----26.8------------ 409.5------------------ 171.3------------------------- 0-3-1
* Rodgers hurt in Week 9
No Rodgers means no ball control by the GB offense which means their D is on the field a lot more now, and they can't stop anyone.. And no Rodgers also means the other team probably has the lead most of the game, and with the lead they're running the ball more.. Look at the rushing yds per game before and after.. It's ridiculous! 77 yds a game is great, they were probably at the top of the league then, 171 yds is worse then awful.
In a cold weather game obviously NO's offense won't be nearly as potent, no offense is, and because IMO their defense really isn't that good, that will be their #1 problem.