Malcolm Butler was named to the Pro Bowl in 2015, but did not play a single snap in the Patriots' loss in the Super Bowl this year.
The Arizona Cardinals announced they had released running back Adrian Peterson.
Peterson, 32, played in six games for the Cardinals last season.
McCown threw for 2,926 yards with 18 touchdowns and nine interceptions in 13 starts with the Jets in 2017.
By releasing Nelson, the Packers now have $10.2 million in cap space.
The often-injured Sam Bradford look set to join the Arizona Cardinals in a deal that could eventually be worth $40million over two seasons.
The New England Patriots are set to lose Danny Amendola to divisional rivals the Miami Dolphins.
The oft-injured Bradford, 30, agreed to a one-year deal with an option year that could pay him up to $40 million if he plays both seasons.
Amendola, 32, averaged 46 receptions and 477 yards over the last five seasons with New England.
Burton's reported four-year deal with Chicago is worth $32 million.