Ball at rest: play or replace?
The R&A / USGA · 2023What changes when wind, the player or an outside influence moves a ball.
Natural forces and outside influences
Normally play a ball as it lies. Wind or water moving a resting ball brings no penalty: play from its new spot. Exceptions require replacement after a ball was lifted and replaced on the green, or when natural forces move a dropped, placed or replaced ball to another course area or out of bounds. A ball moved by an outside influence is replaced without penalty when that cause is known or virtually certain.
Movement caused by a player
Lifting, deliberately touching or moving your resting ball normally costs 1 penalty stroke and requires replacement. Important exceptions cover authorised actions, accidental movement while finding or identifying a ball, and accidental movement on the green. If the ball starts moving during the backswing and you complete the stroke, do not replace it; assess any penalty for causing movement. A moved ball-marker must also be restored, or the ball replaced.
Sources & approach ↗