What happens if your ball moves after grounding the club?

The situation

You sole your club behind the ball on a sloped lie and the ball starts rolling forward, or you set the club down lightly in the rough and the ball shifts position.

The rule

Under Rule 9.4b, if grounding the club causes the ball to move, the penalty is 1 stroke and you must replace the ball before playing. The critical question is causation: did grounding the club (even lightly) cause the movement, or was the ball already shifting due to wind or an unstable slope? In practice, if the ball moves immediately after you ground the club, it's generally attributed to you and the penalty applies.

Real example

You're on a downslope lie, sole the club behind the ball, and it rolls three inches down the hill toward you. That's a 1-stroke penalty — add the stroke, replace the ball in the original spot, then play.

What to do on the course

• Add 1 penalty stroke to your score
• Replace the ball in the original spot before playing your next shot
• If the original position is uncertain, estimate it as accurately as possible
• Consider hovering the club above the ball (not grounding it) on tricky sloped lies to avoid this situation

Penalty

1-stroke penalty if grounding the club caused the ball to move. No penalty if natural forces independently caused the movement.