Writers of Pro Football Prospectus 2008

29 Dec 2006

FO Mailbag: Minnesota defense

Craig Rotz: In your opinion, what were the keys to the Vikings going from 19th in defensive DVOA in 2005 to fourth this year? Also, they are the league's worst pass defense now at 238 yards per game, according to the NFL stats, but Football Outsiders has them at 17th. What do your stats show that has them only middle of the pack against the pass?

Aaron Schatz: The first important issue here is that the NFL's official system of rating pass defenses by total yards allowed may be the dumbest statistic in all of sports. Think of all the things that statistic does not take into account. It doesn't consider how many attempts were required to gain those yards. It doesn't consider turnovers. It doesn't consider strength of schedule. It doesn't consider that when a team is losing games, opponents stop passing the ball because they are running out the clock. And it doesn't consider the opposite of that: that when a team is allowing fewer than three yards per carry, nobody in their right mind is going to want to run the ball against them.

That's what is going on with the Minnesota defense. The opposing offense passes on Minnesota two-thirds of the time, which is far and away the highest percentage in the league -- and the other teams at the top are all teams with winning records.

1. MIN 66.9%
2. BAL 61.7%
3. CHI 61.4%
4. SD 61.0%
5. NE 60.2%

The Vikings have faced 29 more pass attempts than any other defense in the league. One other issue not addressed in the official NFL rankings: Minnesota is third in the NFL with 21 interceptions.

The improvement really came last year, though, not this year. They finished 19th in defensive DVOA for the season, but the Vikings had a totally different defense in the second half of the season.

• Weeks 1-8: 15.1% DVOA, 28th
• Weeks 9-17: -10.1% DVOA, 9th

So this is just a continuation of that. Young players like E.J. Henderson and Kenechi Udeze have matured and improved, while Pat and Kevin Williams have just been playing out of their gourds this year. Pat Williams should have made the Pro Bowl.

Posted by: Aaron Schatz on 29 Dec 2006