A lot of things went wrong for the Oakland Raiders defense in 2014. But of all of those things, the worst one occurred before the season even started.
The Oakland defense looked to be set at linebacker. With two stud playmakers on the outside and a steadying presence in the middle in the form of Nick Roach, the linebackers were primed to be the defense's strongest unit.
But a season-ending head injury to Roach in the preseason stopped this unit from reaching its potential. The entire defense—not just the linebackers—never recovered from this loss.
The Raiders tried using a few different players to fill the gaping hole left in the defense, but nothing worked.