With so many offenses spreading the field with multiple-receiver sets, it's difficult to underrate the importance of having a versatile safety. A safety who can match up against the slot receiver, defend the run and blitz helps negate the advantages that spread sets generally give the offense. Having two versatile safeties on the roster is even better because the offense can't assume what either is going to do at the snap of the ball.
Two safeties who have played a big role in their defense's success in recent years and would normally be on this list are Baltimore's Ed Reed and Will Demps. Reed doesn't have great size, but he is an excellent open-field tackler who fills hard when he reads run, shows good closing speed when blitzing and is a playmaker in coverage.
Although Demps isn't as flamboyant or explosive as Reed, he shows good instincts in coverage and is also a sound run-defender who tackles well. Unfortunately for Ravens fans, a high-ankle sprain has slowed Reed (he's missed six games), and Demps sustained a season-ending knee injury three weeks ago.