When a golfer must lift his ball from the ground, he uses a marker. Normally, the need to pick up a ball is restricted to the green, but occasionally you may have to pick up a ball from elsewhere on the course to identify the ball, replace the ball if it is damaged, or -- if the rules permit -- to clean the ball. No matter the circumstance that causes a player to lift his ball, it must be marked properly.
A ball marker is typically a small disc, such as a coin “or other similar object,” according to Rule 20-1 of the Rules of Golf. However, United States Golf Association Decision 20-1/16 explains that Rule 20-1 merely suggests the best object with which to mark the ball, but doesn’t mandate a particular item. That decision states that a tee, a loose impediment or a golf club may all be used to mark a ball. Scratching a line into the green, while not recommended because the act may damage the surface, is also permitted. An existing mark on the green that happens to line up behind the ball may not be considered a marker.
How to Mark a Golf Ball
A note that accompanies Rule 20-1 says the player should place a marker “immediately behind the ball.” The main exception to this rule occurs when the marker interferes with another player’s stance or the marker may interfere with another player’s shot. In those cases the marker is set down one or more club head-lengths to the side. In all cases, the player must always set her marker down before lifting her ball.
Where to Mark the Ball
Placing the marker behind the ball is a recommended best practice. Pursuant to USGA Decision 20-1/19, a player may place his marker to the side or in front of the ball. But if he sets his marker in front of a ball on the green he must not improve the line of the putt or risk a violation of Rule 13-2, which requires a golfer to play the ball as it lies. A player may not place a marker 2 inches behind the ball because the positioning is not sufficiently accurate, according to Decision 20-1/20.
Accidentally Moving a Ball Marker
Under Rule 20-1, no penalty is assessed if a marker is accidentally moved while a player marks or lifts her ball, provided the marker is replaced as close to the original location as possible. Any other movement of the marker by the player or his caddie, even by accident, results in a 1-stroke penalty. If an opponent or her caddie moves a ball marker accidentally, it must be replaced as near as possible to the original location -- with no penalties assessed -- according to Decision 20-1/7.