Rule 9 – Ball at Rest Lifted or Moved is a rule you need
to know, especially on the putting green.
Because a golf ball is round and the surface of the green closely mown, there is every likelihood that your ball could move. It is important for you to know how to deal with this situation.
What this all means is that for your ball to move on the putting green is easier than you think; especially if the surface has been closely mown, your ball is on a slight slope, and the wind is blowing.
Fortunately the circle of contact that your ball has on the putting green is larger than one dimple as it sits down a little in the grass.
On a soft green with more grass to support its weight, the circle of contact could be around four to five per cent of the ball's surface area.
The Definition in the Rules of Golf under the heading Moved states that when a ball has moved when it has left its original spot and come to rest on any other spot, and this can be seen by the naked eye (whether or not anyone actually sees it do so).
A player's ball at rest is treated as having moved only if it is known or virtually certain that it did.
Sometimes when you come to replace your ball after marking it, it rolls forward ever so slightly down the slope.
The temptation is to replace your ball and press it lightly into the ground to make it remain at rest.
However, there is nothing in the Rules that permits you to do so. Instead you are required to find the nearest spot, no closer to the hole, where your ball can be placed without rolling away.
Rule 13.1d states that there is no penalty if the player, opponent or another player in stroke play accidentally moves the player's ball on the putting green.
The player must replace the ball on its original spot (which if not known must be estimated).
Playing by the Rules is part of Golf and Rule 9 – Ball at Rest Moved takes on an added significance on the putting green.