MILWAUKEE (AP) - The Green Bay Packers have released veteran left tackle Chad Clifton. Clifton is a native of Martin, Tennessee. Packers general manager Ted Thompson called Clifton an "integral part of our success over the past 12 seasons," thanking him for his time with the team. It was not immediately clear whether Clifton will retire. ESPN reported the Packers' plans to release Clifton earlier Monday. Clifton has been the Packers' primary left tackle since 2000, starting 160 regular-season games in 12 seasons. He played only six games last season with hamstring and back injuries, and backup Marshall Newhouse played fairly well in his place. Clifton also played in the Packers' playoff loss to the New York Giants, but was replaced by Newhouse in the third quarter.