One of the two fundamental principles of the Rules of Golf is that you play the ball as it lies. There are a number of times when the ball is moved from its original spot or the player is allowed to lift the ball, but then the ball has to be returned to its original place. The method for putting the ball back is called replacing.
There are only two people who may replace the ball:
If someone else replaces the ball on the correct spot and you play it without correcting the mistake, you get one penalty stroke.
Replacing a ball is almost exactly what it sounds like. You need to put the original ball (you cannot substitute a ball when replacing) back on the required spot by setting it down on that spot and letting it go. If you do it differently (such as by rolling it into place), but still get the ball on the right spot – you get one penalty stroke.
Where your Golf Ball is Replaced
Sometimes when a ball is lifted or moved, it was originally touching some other fixed or attached object. If that’s the case, then you need to make sure to put your ball back in the original position in relation to that fixed or attached object, whether that means on top of, underneath or leaning against it. This doesn’t apply to movable objects such as loose impediments or movable obstructions which might get moved in the process of lifting the ball and those objects do not need to be replaced.
When Your Golf Ball Won’t Stay at Rest
If you replace the ball and it does not stay at rest on the spot, you must try one more time. If the ball still does not stay at rest on that spot, then you find the nearest spot, no closer to the hole and in the same area of the course where the ball will stay at rest.