Green Bay's porous pass defense

The Green Bay Packers are 8-0, but their pass defense is a serious issue. Jeremy Brevard/US Presswire

This week's "Monday Night Football" host, the Green Bay Packers, have raced out to an 8-0 start in their quest to become the first team to repeat as Super Bowl champion since the New England Patriots in 2004. Over the first half of the 2011 season, one glaring team weakness has emerged unexpectedly, which has the potential to prematurely abort their mission. Namely, Green Bay's pass defense has gone from asset to liability faster than Netflix's ill-fated Qwikster experiment.

Casual observers haven't really noticed this development because, well, Green Bay has yet to lose. As long as the Packers win, who cares if now-benched Kyle Orton and having-his-worst-year-as-a-starter Philip Rivers each throw for more than 8.4 yards per attempt against them, right? Much to their credit, some people, like Jason Lisk of Big Lead Sports, have taken note, and detailed just how bad the Packers' pass defense is in comparison to 8-0 teams of the past quarter-century.

Let's take this a step further, though. What does Green Bay's pass defense performance thus far this season say about the likelihood that they'll even reach Super Bowl XLVI, let alone win it? Furthermore, regardless of the answer to that question, what exactly has turned the most efficient pass defense in the NFL last season according to Football Outsiders' DVOA metric into the No. 20 unit this season?

No matter the type of statistic one looks at, the answer to the first question seems to be, "If they don't improve, they probably won't make the Super Bowl." For instance, according to their rankings in traditional stats like yards allowed per attempt (YPA) and net yards allowed per attempt (NYPA) -- the latter of which includes sacks and sack yardage -- the Packers' pass defense in 2011 would rank at or near the bottom of the 90 teams that have reached the Super Bowl over the past 45 years. Specifically, their YPA ranking (24th) would be the second-worst among Super Bowl participants, ahead of only the 1999 Tennessee Titans (27th), and their NYPA ranking (26th) would be the worst ever.