This common practice could get you in trouble.
Back in 2019, the LPGA Tour found itself in the spotlight for a curious ruling involving two tour players and a practice called “backstopping”. If you’ve never heard the term, it’s commonly used to describe purposely leaving a ball in place on the putting green instead of marking it. The thought is that it can potentially help another player who is hitting an approach shot onto the green. If the player off the green hits a shot that is too hot, the ball on the green might stop another from getting into real trouble.
Rule 15.3a covers this practice and, as you might guess, it’s illegal (a two-stroke penalty for each player who makes the agreement).
Getting back to the incident on the LPGA Tour, Ariya Jutanugarn and Amy Olson were paired in the same group at the Honda LPGA Thailand and reached the final hole of the second round with Jutanugarn’s ball on the green and Olson’s just off. Jutanugarn did not mark her ball, and Olson’s ensuing chip struck it. The incident got a lot of attention because the two players fist-bumped afterwards, suggesting there might have been some collusion. However, the LPGA ruled that they did not agree to leave the ball in place.
Setting aside your opinion on that incident, there was a bunch of talk on the pro tours about the practice in the ensuing months, with major champion Jimmy Walker even admitting he did it from time to time to help others.
What you need to know about Rule 15.3a is that in strokeplay, regardless of whether you are aware of the rule, you can’t agree to leave your ball to help another player – or vice versa. Ignorance is not going to get either of you out of that two-stroke penalty. Worse, if you both know it’s illegal and did it anyway, you both would be disqualified under Rule 1.3b(1) for deliberately ignoring a rule.
Interestingly, in matchplay there is no penalty if you do it for your opponent because any benefit that might come from the agreement affects only your match, a clarification to the rule states (15.3a/2).
The smart move is to mark and lift your ball if you think it might help another player who is about to chip. Keep in mind that in strokeplay, you can also elect to hit the putt before the player chips because there is no penalty for playing out of order.
Returning to the example of what happened in the LPGA tournament, procedurally if there was no intent to backstop and the ball on the green was struck, that ball must be replaced in its original spot. Meanwhile, the ball that hit the resting ball on the putting
surface is played as it lies (Rule 11.1).
