What happens if the ball moves on the putting green?

The situation

Your ball is on the green, waiting to be putted, and it moves — either rolling on its own down the slope, blown by the wind, or accidentally nudged by you, your partner, or another player in the group.

The rule

The cause determines everything. Under Rule 13.1d, if natural forces (wind, gravity on a slope) move your ball on the green, no penalty and you play from the new spot. If you or your caddie accidentally move it, that's Rule 9.4b: 1-stroke penalty, replace the ball. If another player moves it accidentally, Rule 9.6 applies: no penalty to either player, replace the ball. One important exception: if your ball was already marked and then replaced, and it subsequently moves due to natural forces, you must replace it — the ball was in a "set" position.

Real example

You're reading your putt and a gust of wind nudges your ball six inches. No penalty — putt from the new spot. But if you accidentally step on the ball while reading the line, that's a 1-stroke penalty — replace it.

What to do on the course

• Wind moved it: no penalty, play from new spot (unless previously lifted and replaced — then replace it)
• You moved it: 1-stroke penalty, replace in original position
• Another player moved it: no penalty, replace in original position
• When in doubt whether wind or your action caused it, the benefit of the doubt goes to natural forces if there's any wind at all

Penalty

No penalty for natural forces. 1-stroke penalty if you or your caddie caused the movement.