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Editor's note: Yahoo! Sports will examine the biggest weakness of the 2009 season for every team and explain how the franchise can address the issue. The series continues with the Vikings, who finished first in the NFC North (12-4).
Biggest problem in 2009: A back four that negates the NFL's best front four
It's safe to say that there aren't too many holes in the Minnesota Vikings' roster. We all know that Brett Favre(notes), who may have had his best season in 2009, is coming back. Adrian Peterson is one of the NFL's most exciting and productive backs, receiver Sidney Rice(notes) had a breakout year, and an offensive line under fire in previous years played at a decent level.
On defense, the Vikings are led by the best front line in the game. End Jared Allen is as dominant a pass rusher as there is in the NFL; when he doesn't get to the quarterback for sacks, he's incessantly hitting and hurrying them. On the other side, Ray Edwards(notes) has used opposing focus on Allen to put up his own outstanding numbers – in the 34-3 playoff win over the Dallas Cowboys, he was unstoppable. And in the middle, Pat and Kevin Williams(notes) comprise a force that has put the Vikings at or near the top in run-stopping metrics every season over the last few years.
But one statistic reveals the Vikings' current primary liability. Minnesota hurried opposing quarterbacks on 23.8 percent of pass plays, the highest in the league, according to Football Outsiders' game-charting data. However, they had the worst Defensive DVOA (Defense-adjusted Value Over Average, FO's per-play efficiency metric) in the NFL when they did so. This was primarily the fault of a secondary that finished the 2009 season ranked 22nd in DVOA against the pass – an inexcusable number given the pass-rush benefits that secondary enjoyed.
Since the Vikings didn't need to blitz, they rushed four (67.7 percent) far more than they rushed five (23.9 percent) or six or more (6.7 percent). And quite often, their blitzes were zone blitzes – they did that on 9.5 percent of their defensive snaps, fourth-highest in the league. With linebackers often in the flats instead of rushing the passer (only three teams had fewer linebacker sacks than the Vikings), it made the problems of the defensive backs all the more acute.
The Vikings are a fairly simple base Cover 2/Tampa 2 team, operating out of the Monte Kiffin/Tony Dungy systems as much as any team in the NFL. Success in these coverages is predicated on personnel as much as scheme, so when cornerback Antoine Winfield(notes) missed six games in midseason with a foot injury, the situation became even more dismal.
The 2010 solution: Optimize linebacker placement for quarterback mistakes
Winfield returned in time for the Week 14 contest against the Cincinnati Bengals, and the improvement was clear in Minnesota's 30-10 victory. Bengals quarterback Carson Palmer(notes) threw for just 94 yards on 15 completions, and receiver Chad Ochocinco(notes) said after the game, "I can only speak from the secondary's standpoint, but [cornerbacks] Cedric Griffin(notes) [and] Antoine Winfield, [and safety] Madieu Williams(notes) – they did a hell of a job."
Still, Palmer exploited the Vikings with short passes to his running backs when all three linebackers bailed too far back into coverage. On third-and-12 from his own 13-yard line and less than a minute elapsed in the first quarter, Palmer took the ball out of shotgun and watched the nickel defense back off (Figure 1). Linebacker Chad Greenway(notes) (52) backed into coverage from a blitz look – in fact, the entire intermediate defense (two linebackers and the nickel cornerback) vacated the zone. With a good 15 yards of free space, Palmer threw to halfback Brian Leonard(notes) (40) on a quick route upfield, and Leonard hit the left seam and gained 13 yards and the first down before right cornerback Cedric Griffin (23) took him down at the 25.
Two plays later, Minnesota took a more measured and successful approach to their intermediate coverage (Figure 2). On first-and-10 from the Bengals' 37, the Vikings brought a zone blitz, with middle linebacker Jasper Brinkley(notes) (54) zooming to the line first, followed closely by weakside linebacker Ben Leber(notes) (51). At the same time, left defensive end Ray Edwards (91) reversed field, covering tight end J.P. Foschi(notes). Palmer didn't get pressured because both backs were blocking out of an offset-I formation, but he also didn't have the hot route this time – with his tight end covered and his backs out of the picture, Palmer had to throw early and downfield to Chad Ochocinco, and his pass was almost intercepted by Madieu Williams (20), who was playing free safety.
The Vikings have optimized their personnel for a specific kind of defense. They have dynamic rushers up front, linebackers who can cover, and defensive backs who are expected to cover consistently more than they are asked to dominate. If they can't do the basics, Minnesota's linebackers will have to be more careful about their spacing concepts.