19-1. By Outside Agency
If a ball in motion is accidentally deflected or stopped by any
outside agency, it is a rub of the green, there is no penalty and
the ball must be played as it lies except:
a. If a 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 player must, through the green or in a
hazard, drop the ball, or on the putting green place the
ball, as near as possible to the spot where the outside
agency was when the ball came to rest in or on it, and
b. If a 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 or an
insect, the stroke is cancelled. The ball must be replaced
and the stroke replayed.
If the ball is not immediately recoverable, another ball may
be substituted.
(Player’s ball deflected or stopped by another ball – see
Rule 19-5)
Note: If the referee or the Committee determines that a
player’s ball has been purposely deflected or stopped by an
outside agency, Rule 1-4 applies to the player. If the outside
agency is a fellow-competitor or his caddie, Rule 1-2 applies to
the fellow-competitor.

19-2. By Player, Partner, Caddie or Equipment
a. Match Play
If a player’s ball is accidentally deflected or stopped by himself,
his partner or either of their caddies or equipment, he loses
the hole.
b. Stroke Play
If a competitor’s ball is accidentally deflected or stopped by
himself, his partner or either of their caddies or equipment, the
competitor incurs a penalty of two strokes. The ball must be
played as it lies, except when it comes to rest in or on the
competitor’s, his partner’s or either of their caddies’ clothes or
equipment, in which case the competitor must through the
green or in a hazard drop the ball, or on the putting green
place the ball, as near as possible to where the article was
when the ball came to rest in or on it.
Exception: Dropped ball – see Rule 20-2a.
(Ball purposely deflected or stopped by player, partner or
caddie – see Rule 1-2)

19-3. By Opponent, Caddie or Equipment in Match Play
If a player’s ball is accidentally deflected or stopped by an
opponent, his caddie or his equipment, there is no penalty. The
player may, before another stroke is made by either side,
cancel the stroke and play a ball without penalty as nearly as
possible at the spot from which the original ball was last
played (see Rule 20-5) or he may play the ball as it lies.
However, if the player elects not to cancel the stroke and the
ball has come to rest in or on the opponent’s or his caddie’s
clothes or equipment, the player must through the green or in
a hazard drop the ball, or on the putting green place the ball,
as near as possible to where the article was when the ball came
to rest in or on it.
Exception: Ball striking person attending flagstick – see
Rule 17-3b.
(Ball purposely deflected or stopped by opponent or caddie –
see Rule 1-2)

19-4. By Fellow-Competitor, Caddie or Equipment in
Stroke Play
See Rule 19-1 regarding ball deflected by outside agency.

19-5. By Another Ball
a. At Rest
If a player’s ball in motion after a stroke is deflected or stopped
by a ball in play and at rest, the player must play his ball as it
lies. In match play, there is no penalty. In stroke play, there is
no penalty unless both balls lay on the putting green prior to
the stroke, in which case the player incurs a penalty of
two strokes.
b. In Motion
If a player’s ball in motion after a stroke is deflected or stopped
by another ball in motion after a stroke, the player must play
his ball as it lies. There is no penalty unless the player was in
breach of Rule 16-1f, in which case he incurs the penalty for
breach of that Rule.
Exception: If the player’s ball is in motion after a stroke on the
putting green and the other ball in motion is an outside agency
– see Rule 19-1b.