Rumors have been swirling of the possibility of the Seahawks trading Richard Sherman. It's not entirely clear if he wants out, or the team is weary of him. What is clear is that he's been part of the league's best pass defense since entering the league.

Prior to Sherman being drafted in 2011, Seattle hadn't ranked in the top 20 in pass defense since 2002 -- nearly a decade. In the six years Sherman has been with the team, meanwhile, Seattle hasn't ranked lower than 11th defending the pass; top-10 five years in a row. Their average ranking over Sherman's six season is 5th -- better than any other team.

It's not all Sherman, but he certainly deserves a healthy share of the credit for a defense that started excelling right at the time he showed up in the lineup.

NFL pass defense rankings over the last six seasons, sorted by average rank, are shown below.

NFL PASS DEFENSE RANKINGS, 2011-2016
Team201120122013201420152016Avg
Seattle11511285th
Houston315321328th
Buffalo1984317710th
Denver1862791110th
Kansas City69252101712th
San Francisco16475261212th
NY Jets522214131512th
Baltimore417122381012th
Arizona17314299513th
Cincinnati911520221113th
Cleveland22488192014th
Pittsburgh11927301915th
Chicago281015304616th
LA Rams719191923916th
San Diego1318294122116th
Carolina2414611152917th
Tennessee1426111573017th
Jacksonville820T262229318th
Detroit22132313181818th
Minnesota262531714418th
Miami2527166211619th
Indianapolis15221312252719th
Green Bay3212241063219th
Philadelphia1073231281420th
Dallas2316302652521st
New England31291817201321st
Atlanta20232132112823rd
Tampa Bay21321728162223rd
Washington12302024272623rd
NY Giants29281018322323rd
Oakland2720T2816242424th
New Orleans3031225313125th

--Andy Richardson