The evolution of NFL offenses has placed a premium on safeties who can do it all. No longer is it enough simply to drop into a Cover-2 shell and keep receivers from breaking free deep. Safeties must be able to stop the run, blitz the quarterback, cover tight ends and wide receivers. An increasing number of defensive systems also ask their safeties to be interchangeable -- in other words, not limited merely to playing the free or strong safety spot, but capable of handling either job at any given time.
It's not an easy job. Some have kept pace far better than others.
Those on our list of the NFL's 10 best safeties have led the way. This is a position deep with talent but relatively limited when it comes to true game-changers.
Vaccaro is on the verge of stardom. He approached that level during a standout rookie season and now, with Jairus Byrd by his side and another year in Rob Ryan's defensive system under his belt, he could turn quickly into a perennial All-Pro. The Ravens have a similar hope for Elam, who played quite well in his debut season.
The rest of the group above consists of take-your-pick veterans. All can be counted on as 16-game starters, with the occasional flash of brilliance. They're outside the top 10 because their spates of inconsistency tend to linger longer than they do for the players to come.
10. Kam Chancellor, Seattle: Richard Sherman and Earl Thomas form an unmatched duo in the Seahawks secondary. Neither would be as effective without Chancellor, an in-the-box safety who allows the rest of Seattle's defensive backs more freedom to turn it loose.
"He is the enforcer," Seahawks defensive assistant Marquand Manuel said, per the team's website. "But he’s the best teammate you could ever have. They hit the jackpot. They lucked out big time when they got this guy in the fifth round. He is a perfect complement to Earl Thomas.”
Chancellor's 99 tackles last season were third on the team, behind only linebacker Bobby Wagner (120) and Thomas (105). He was charged with just eight missed tackles, an extremely low failure rate on a high number of chances. The 26-year-old Chancellor may not be as irreplaceable as his higher-profile defensive teammates ... but he's close.
9. Eric Reid, San Francisco: There were 23 safeties drafted in 2013, and though the likes of Elam and D.J. Swearinger found their way into starting lineups, it has been Reid and Vaccaro pacing the way for the rookie crop. For now, give the edge there to the 49ers' guy. With Vaccaro sitting out a pair of games to injury, Reid finished with more tackles and more interceptions while also earning a Pro Bowl nod. Rather remarkably, Reid also made it through his rookie season without committing a penalty.
8. Donte Whitner, Cleveland: Reid's copilot last season will be T.J. Ward's replacement in Cleveland this season, as the NFL's safety world turns. There may be some drop-off there, particularly against the run, but odds are that it will not be too noticeable. Whitner is less of a force near the line than Ward -- who has earned a higher spot on this list mainly due to his run-stuffing skills -- but he is a rangier option on the backend.
Whitner can walk a very fine legality line with his play -- he was the most penalized safety in the league last season, hence his earlier desire to change his name to "Hitner." His reputation as a punishing defender precedes him when receivers venture over the middle.
7. Troy Polamalu, Pittsburgh: At the close of the 2012 season, just about everyone thought that Polamalu was approaching the end of the line. He missed nine games that year, and when he was on the field his declining health left him less aggressive and far less effective in his free-wheeling role.
But then 2013 arrived. Polamalu may not have been a replica of his 2010 Defensive Player of the Year self last season, but he appeared to find the fountain of youth en route to a Pro Bowl performance. More importantly, he played all 16 games, quieting for the moment questions about his ability to stay on the field. Like a pitcher who loses his fastball, Polamalu has adjusted his game. Though he's not the dominant run-stopper he once was, Polamalu was as solid against the pass in 2013 as he has been in some time.
6. Devin McCourty, New England: Last year was the first that saw McCourty in a full-time safety role, and let's just say that it worked. There remains work to be done in rounding out McCourty's game at his new position, but his corner skills came in handy as he quickly established himself as an elite coverage safety. The results should only get better as McCourty finds his comfort zone.
5. Eric Weddle, San Diego: Often overlooked -- Weddle's omission from the Pro Bowl and All-Pro teams in 2012 was a joke -- Weddle continues to be the Chargers' defensive leader. He did earn his second Pro Bowl nod in 2013 on the strength of 115 tackles. Weddle really does it all, even providing eight quarterback hurries and a sack last season.
4. T.J. Ward, Denver: Already hinted at this above, but Ward is the league's preeminent run-defending safety right now. The new Bronco notched 112 tackles in his final Cleveland season, enough to earn him Pro Football Focus' top rating versus the run at his position. This is nothing new -- Ward finished his rookie season of 2010 with 123 tackles and topped that same PFF rating back in '12.
3. Jairus Byrd, New Orleans: While Byrd more than holds his own against the run, it is in defending the pass that the newest Saint truly shines. What Ward is to the opposition's ground game, Byrd is to the aerial attack.
Byrd hauled down four interceptions last season and 22 total over his five years with the Bills. He's perfectly comfortable playing a solitary center-field spot in Cover-1, which will come in handy in Rob Ryan's aggressive defense. Ryan also will not and should not hesitate to use him in a variety of ways, from stepping up against the run to covering tight ends in the slot.
2. Eric Berry, Kansas City: A three-time Pro Bowler and, as of 2013, an All-Pro, Berry deserves all the accolades he has received over his first four NFL seasons. Remember, he lost one of those years -- 2011 -- to a Week 1 knee injury. He returned in fine form the next season, then took his game back to an elite level in '13.
The Chiefs move Berry all over the field, something that his improved coverage skills have permitted. Berry stormed into the league with a Pro Bowl rookie campaign; four years later, he is a far more refined and complete safety, quite a ways removed from the in-the-box dynamo of 2010.
1. Earl Thomas, Seattle: If the Seahawks had to choose between either Richard Sherman or Earl Thomas, which way would they go? The answer quite honestly should be Thomas, even taking into account how dominant a lock-down cornerback Sherman has become.
The money spent this offseason on Byrd, Ward, Whitner and others, plus teams' consistent over-drafting of safety prospects highlights just how desperate front offices are to find a superstar at that position. Thomas is there, having started every single game for Seattle since being a first-round pick in 2010, with three straight Pro Bowls and back-to-back All-Pro honors under his belt.
Chancellor's presence certainly offers Thomas incredible support, as does Sherman's propensity for shutting off one side of the field. Both those players are better because they know that Thomas is behind them, with his high-end speed and a brilliant ability to diagnose what's developing in front of him.