"Concrete Charlie" played a long time ago.
Chuck Bednarik famously is remembered as the NFL's last 60-minute man, never coming off the field as he played center, linebacker and special teams for the Philadelphia Eagles.
Bednarik retired after the 1962 season. Since then there have been many players who have played one side of the ball and seen snaps on the other side, but that's rare. And the list of players like Travis Hunter, who could go No. 2 in the NFL Draft to the Cleveland Browns and has a chance to play regularly at cornerback and receiver, is very small.