The GCAA is partnering with the USGA, represented by Jamie Wallace, to do a feature on the Rules of Golf focusing on common situations that players encounter. Each month, we plan to highlight a specific Rule or Rules situation that is relevant to college golfers or one that is often misunderstood. We will highlight what the Rule says and how it is applied to the situation at hand.

This month, Jamie takes a closer look at what happens when a ball at rest is struck by another golf ball.

The above video is one of my favorites because of the almost unbelievable timing. It shows Carl Pettersson preparing to play his second shot into the fifth hole at Merion Golf Club during the 2013 U.S. Open. As he starts his backswing, qualifier Brandon Crick's errant tee shot from the adjacent second hole comes rolling down the severely sloped fairway and strikes Pettersson's ball.

At first glance, this might seem like a confusing scenario, but it is actually quite simple to resolve.

Crick's ball is played as it lies from where it comes to rest. The Rules call this a rub of the green and it is covered under Rule 19-5. Pettersson simply replaces his ball on the spot from which it was moved, which is covered under Rule 18-5. Pettersson will place his ball if the exact location is known, or if not, he will drop it at the estimated spot (covered under Rule 20-3c). There is no penalty to either player.

Now let's take a look at another related situation.

This one is from the 2014 U.S. Women's Open at Pinehurst and involves Emma Talley (winner of the 2015 NCAA Division I Women's Championship) and Inbee Park. Talley's tee shot on the par-3 ninth hole lands on the green and then strikes and moves Park's ball.

Just like in the Pettersson video above, Talley's ball will simply be played from where it came to rest. The position of Park's ball prior to being moved will be estimated, and the ball will be replaced on that spot. Even if she did not know the exact spot, Park's ball would still be placed (rather than dropped) in this situation since her ball lies on the putting green. Again, there is no penalty to either player.

Both of the situations above involved strokes from somewhere other than on the putting green. The only time a penalty is potentially involved is when there is a collision between two balls that both lay on the putting green prior to the stroke.

Let's use the following scenario as an example. Player A strikes a putt from the putting green, and A's ball strikes Player B's ball, which was at rest on the putting green before A played.

In match play, there is still no penalty to either player. Player A plays his/her ball as it lies, and Player B replaces his/her ball. In stroke play, we encounter the one situation where a penalty is involved. Player A will be penalized two strokes since both balls lay on the putting green prior to the stroke. Just as in match play, A will play his/her ball as it lies and B will replace his/her ball.

If you have a Rules question that comes up in a tournament this spring or that happened during a past round, feel free to send it in to us at gregg@collegiategolf.com and perhaps we will address it in a future newsletter. If you have any questions about the topics discussed here, or have any other Rules of Golf questions, please feel free to contact the USGA Rules department at 908-326-1850 (available seven days a week) or rules@usga.org.