Playing by the book What golf’s rules say

RULE 19-1

If a player’s ball in motion is accidentally deflected or stopped by any outside agency there is no penalty and the ball must be played as it lies, except: a) If a player’s ball in motion after a stroke other than on the putting green comes to rest in or on any moving or animate outside agency, the ball must through the green be dropped, or on the putting green be placed, as near as possible to the spot directly under the place where the ball came to rest in or on the outside agency but not nearer the hole, and b) If a player’s ball in motion after a stroke on the putting green is deflected or stopped by, or comes to rest in or on, any moving or animate outside agency, except a worm, insect or the like, the stroke is cancelled. The ball must be replaced and replayed.