The team released Thompson on Monday, and he said in a statement that he intends to retire from football. Thompson hurt his neck during a Packers practice last season, and team officials initially hoped he could continue his career.
Thompson, a fourth-round pick in the 2008 draft, thanked the team and fans in a statement.
"I have consulted with a number of physicians, and due to my medical condition my intention is to retire from football," he said. "I am thankful to the Packers organization and to the fans for their support during my time in Green Bay. The Packers are a first-class organization and I want to thank them for the opportunity to play in the NFL. There truly is no team I would have rather played for."
Thompson was hospitalized after injuring his neck in a collision during a practice in December. He was unable to play the remainder of the season. Brad Jones and Brady Poppinga are the most likely candidates at outside linebacker to start opposite Clay Matthews III next season.
Peprah played in 37 games for the Packers between 2006 and 2008 and appeared in two games for Atlanta last season.
Frischknecht spent the 2009 season on injured reserve after signing with the Packers as an undrafted free agent last summer.