What happens if the ball moves after a practice swing?

The situation

You take a practice swing and your club catches the grass near the ball, causing it to roll. Or you swipe through the air and the wind from the club head is enough to move the ball an inch.

The rule

Under Rule 9.4b, if your practice swing causes the ball to move, it's a 1-stroke penalty and you must replace the ball. There is one important exception: in the teeing area before you make your first stroke on the hole, you may re-tee the ball with no penalty even if a practice swing knocked it off the tee (Rule 6.2b). Outside the teeing area, the 1-stroke penalty applies.

Real example

You're in the fairway, take a practice swing through the grass about a foot behind the ball, and the follow-through accidentally clips the ball, rolling it two feet forward. 1-stroke penalty — replace the ball in the original spot, then play your shot.

What to do on the course

• On the tee (first stroke): no penalty — re-tee and play
• Anywhere else: add 1 penalty stroke and replace the ball before playing
• The practice swing itself does not count as a stroke (you had no intention of hitting the ball)
• Only the penalty stroke is added — your next shot is played from the replaced position

Penalty

1-stroke penalty (except in the teeing area before the first stroke of the hole, where there is no penalty).