The Jaguars received cornerback David Jones and a conditional draft pick in the deal, completed after teams made final cuts to reach the 53-man roster limit.
Nelson was the 21st overall pick in 2007 out of Florida. He had an impressive rookie season -- 82 tackles, five interceptions, two forced fumbles and a sack. Since then, he has posted just two interceptions, and his tackles total has dropped.
Nelson shifted positions in Jacksonville after starting as a roaming safety. He spent time at cornerback and was part of nickel pass defenses. The three-year starter lost his job this season, playing at safety with the reserves during preseason games.
That leaves Anthony Smith, Sean Considine, Tyron Brackenridge and Courtney Greene at safety and a void at nickel back.
The Associated Press contributed to this report.