27-2. Provisional Ball

a. Procedure

If a ball may be lost outside a water hazard or may be out of bounds, to save time the player may play another ball provisionally in accordance with Rule 27-1. The player shall inform his opponent in match play or his marker or a fellow-competitor in stroke play that he intends to play a provisional ball, and he shall play it before he or his partner goes forward to search for the original ball.

If he fails to do so and plays another ball, such ball is not a provisional ball and becomes the ball in play under penalty of stroke and distance (Rule 27-1); the original ball is deemed to be lost.
(Order of play from teeing ground - see Rule 10-3.)

b. When Provisional Ball Becomes Ball in Play

The player may play a provisional ball until he reaches the place where the original ball is likely to be. If he plays a stroke with the provisional ball from the place where the original ball is likely to be or from a point nearer the hole than that place, the original ball is deemed to be lost and the provisional ball becomes the ball in play under penalty of stroke and distance (Rule 27-1).

If the original ball is lost outside a water hazard or is out of bounds, the provisional ball becomes the ball in play, under penalty of stroke and distance (Rule 27-1).
If there is reasonable evidence that the original ball is lost in a water hazard, the player shall proceed in accordance with Rule 26-1.

Exception: If there is reasonable evidence that the original ball is lost in an immovable obstruction (Rule 24-2c) or an abnormal ground condition (Rule 25-1c), the player may proceed under the applicable Rule.

c. When Provisional Ball to be Abandoned

If the original ball is neither lost nor out of bounds, the player shall abandon the provisional ball and continue play with the original ball. If he fails to do so, any further strokes played with the provisional ball shall constitute playing a wrong ball and the provisions of Rule 15 shall apply.

Note: Strokes taken and penalty strokes incurred solely in playing a provisional ball subsequently abandoned under Rule 27-2c shall be disregarded.