Josh Sitton has been one of the stalwarts up front for Green Bay since 2009, but the Packers are ready to part ways.
The Packers have now released three-time Pro Bowler Sitton, they announced on Saturday.
Sitton, a fourth-round pick of the Packers in 2008, has started every game but two for Green Bay since 2009. He was a key piece up front for Green Bay's Super Bowl run in 2010.
"We want to thank Josh for his contributions during his time in Green Bay," Packers general manager Ted Thompson said.
"He has been an important part of the success we have enjoyed on the field. While these decisions are never easy, this was done with a focus on what is best for the team and the growth of the offensive line.
"We wish Josh and his wife, Kristen, all the best in the future."
The decision comes as a huge surprise and Sitton will not stay on the market long.
"I'm very optimistic of his prospects for playing for a number of additional years," Sitton's agent, Jack Reale, told ESPN.
"He's coming off of maybe his best camp in the last four years. He's lighter, and he is in better shape. He is coming off of a Pro Bowl season and he just turned 30.
"I think he's got lots left. I think all the teams that he has been playing against for the last several years are certainly aware of that, and certainly teams within their division. So we will see what happens."
The Packers have several options to replace Sitton, including using Lane Taylor and Don Barclay. They could also slide right tackle Bryan Bulaga to guard and play second-round pick Jason Spriggs, a rookie from Indiana, at tackle. Another option is using Tretter at guard once Corey Linsley's hamstring has fully healed.
The Packers are also releasing inside linebacker Sam Barrington, who started eight games over the last two seasons.