After being a consistent Super Bowl contender throughout much of AdvancedNFLStats.com, no San Diego Charger front-seven member ranked higher than 30th at his position in terms of Win Probability Added (WPA), while only safety Eric Weddle was a top-tier player in the secondary.

If not for their defense, San Diego would have almost easily been an 11-win team.

What Should They Do?

From a free agent perspective, the Chargers top priority this offseason will be linebacker Donald Butler. Though he’s had trouble with his health over the last couple of seasons, Butler’s the team’s best linebacker, and losing him would only make a struggling defense even worse.

Moreover, expect the Chargers to do something about their secondary, specifically at the cornerback position. Though it improved down the stretch last season, the pass defense was a huge weakness. No corner finished higher than a 48 ranking in terms of WPA last year for San Diego. That’s atrocious.

In all, the Chargers made a nice jump in 2013 after failing to make the playoffs in their three previous seasons. They have some building to do on the defensive side of the ball, and because Philip Rivers may be limited with age, they’ll need to start making moves quickly in order to make this team a legitimate contender.