NFL.com reported on Monday that Burnett signed a four-year, $24.75 million extension.
Burnett, a third-round pick from Georgia Tech in 2010, has started all 36 games in which he has appeared in three seasons with the team. He has 259 tackles, 28 passes defensed, six interceptions, four forced fumbles, three fumble recoveries and three sacks.
The Packers also released wide receiver Terrell Sinkfield.
Information from The Associated Press was used in this report.