The Hall did not disclose details in its statement Friday.
Gregg starred at tackle and guard for the mighty Packers teams of the 1960s. Green Bay coach Vince Lombardi called him the “best player I ever coached.”
Gregg began his NFL career in 1956 and played a final season with the Dallas Cowboys in 1971. He went on to coach in the NFL for 11 years.
He played on NFL/NFC championship teams and three Super Bowl winners. He was elected to the NFL's all-decade team of the 1960s and its 75th anniversary team.