What's wrong with Buffalo's D?

Mario Williams and the Buffalo defense appear to be heading for the "enigmatic" label. Rich Schultz/Getty Images

The Buffalo Bills have had an up-and-down season in the early going. At 2-2, they are in a three-way tie atop the AFC East. They've beaten the Kansas City Chiefs and Cleveland Browns with strong defense and a potent offensive attack. But against the New York Jets in Week 1, and the New England Patriots on Sunday, they got blown out. And the defense looked awful.

As I wrote in my debut column for ESPN Insider, the Bills should be having an easy time switching to a 4-3 under defensive coordinator Dave Wannstedt this season. It's easier to go to a 4-3 from a 3-4 than vice versa, and they played some 4-3 hybrid looks last year. Plus, Buffalo brought in players like Mario Williams and Mark Anderson in free agency (who excelled in 4-3 systems), and drafted cornerback Stephon Gilmore to shore up the secondary.

But the growing pains are obvious.

In its two losses this year, Buffalo has given up 48 and 52 points, respectively. New England scored 35 unanswered points in the second half on Sunday. A game like that might make you think the move has been exposed as a disaster, but was this just a case of a bad matchup against the Patriots, or is something wrong with Buffalo's defense?