Matthews, 26, has 42.5 sacks in his four seasons with the Packers, including 13 last season. He has 204 tackles, seven forced fumbles and four interceptions in 58 career games since being drafted 26th overall in the 2009 draft out of USC.
The Packers are also working on an extension for Aaron Rodgers, with sources saying last week the sides are closing in on a long-term deal that would make the quarterback the highest-paid player in NFL history.
The first day of Green Bay’s offseason workout program is April 15. Rodgers' and Matthews' agents are going to want their clients' deals in place before the players step back on the field, according to sources.
Both Rodgers and the Packers are hesitant to comment on a potential extension, but leaguewide speculation is that the deal could average $25 million per year.
Both sides have been extremely careful when publicly commenting on a deal. But those familiar with the contract talks believe a deal will be completed this offseason.
Rodgers was asked about the contract talks in a radio interview Tuesday.
"We'll see what happens here. I don't have an answer for you," he told 102.9 FM in Milwaukee.
A former Super Bowl MVP, Rodgers is under contract through 2014, having signed a six-year, $65 million contract in October 2008. Rodgers' base salary in 2013 is $9.25 million, while his 2014 deal is worth $10.5 million.