GREEN BAY, Wis. -- One of the biggest fan favorites on the Green Bay Packers' roster will head to the open market.

Veteran fullback John Kuhn will not have a new contract before the start of free agency Tuesday, according to a source familiar with the negotiations.

The source said the sides planned to keep in touch, leaving open the possibility that Kuhn could return for an eighth season with the Packers.

The Packers won't offer popular fullback John Kuhn a contract before the start of free agency Tuesday. Jonathan Daniel/Getty Images

Kuhn is one of 17 players on the Packers' roster from last season due to become an unrestricted free agent. The 31-year-old was last a free agent following the 2010 season. After the NFL lockout of 2011, he re-signed with the Packers for $7 million over three years, including a $750,000 signing bonus.

He specialized as a short-yardage back and often was greeted with cheers of "Kuuuuuhn" when he took the field. He also excelled as a blocker and on special teams. On perhaps the most memorable play of last season for the Packers -- Aaron Rodgers' game-winning, 48-yard touchdown pass to Randall Cobb in the final minute of the regular-season finale against the Chicago Bears -- Kuhn made the key block to slow defensive end Julius Peppers. Had Kuhn not gotten a piece of Peppers, he would have had a clear path to Rodgers.

"I have to say he's probably the best pass protector, third-down back in the league as far as protection," Alex Van Pelt, who coached Packers running backs last season, said shortly after the season. "At certain points, you have a comfort level with John that's huge. That would be a hole we'd have to fill."

Coach Mike McCarthy said earlier this offseason that he wants the running backs, including last season's offensive rookie of the year Eddie Lacy, to become better on third down so that they don't have to come out of games and slow the team's no-huddle offense. That was a sign that Kuhn's value to the team might be minimized.

The Packers have one other fullback on the roster, Ina Liaina, who was signed as a free agent Jan. 28.