One of the reasons the Carolina Panthers hired head coach Ron Rivera before the 2011 season is that the man knows how to turn a defense around. And the Panthers certainly needed that help — in 2010, their defense ranked 16th in Football Outsiders’ opponent-adjusted metrics, dropping to dead last in Rivera’s first year. But over the 2012 and 2013 seasons, while all the focus was on Cam Newton’s quarterback development and body language, Rivera and defensive coordinator Sean McDermott were building a fairly titanic front seven — the kind that could compete with any in the NFL when the conversation came around to the league’s best in that department. The 6-3 Panthers are buttressed by Luke Kuechly’s legitimate Defensive Player of the Year candidacy, linebacker Thomas Davis is criminally underrated, and if you want to see an active and effective defensive line in everything from base fronts to advanced blitzes, this group is as good as it gets. Carolina currently ranks first in FO’s metrics, and only the Kansas City Chiefs have allowed fewer yards and points this season.