WHAT IS A GOLF BALL MARKER? A Golf Ball Marker is a small, flat metal object used to mark the position of a golf ball when the ball is lifted on the putting green. The ball marker is placed directly behind the golf ball before the ball is lifted. By placing a marker, you can pick up your ball, so that another golfer can putt without being distracted. The ball is then replaced directly in front of the ball marker, on its original spot when it's time to putt.