Rules Corner

Ball At Rest Moved By Another Ball

 Permanent link   All Posts


OMAHA, Neb. – During the 2013 U.S. Senior Open, two incidents occurred where a player’s ball at rest was moved by another player’s ball in motion. In both cases the ball in motion was played as it lies (Rule 19-5a, Ball in Motion Deflected or Stopped; By Another Ball At Rest). In the cases of the balls at rest that were moved, they were both replaced (Rule 18-5, Ball at Rest Moved; By Another Ball).

In the first round, Mark O’Meara’s tee shot to the par-3 16th green struck Mark Calcavecchia’s ball, which was already on the green and at rest. The collision moved Calcavecchia’s ball more than 20 feet. Rule 18-5 (Ball at Rest Moved; By Another Ball) says, “If a ball in play and at rest is moved by another ball in motion after a stroke, the moved ball must be replaced.” If you are wondering if there was a penalty, the answer is no. In order for there to be a penalty, the Rule would have to specifically say there was one, and the language in Rule 18-5 does not include any reference to a penalty.

However, in replacing his ball, Calcavecchia had a little problem. Since he was more than 200 yards from his ball when it was moved and because the collision with O’Meara’s ball had not left any noticeable mark on the putting green, he didn’t know exactly where to replace his ball. Rule 20-3c (Placing and Replacing; Spot Not Determinable) provided the help Calcavecchia needed.  It says, “If it is impossible to determine the spot where the ball is to be … replaced…on the putting green, the ball must be placed as near as possible to the place where it lay but not in a hazard.” With the help of spectators, Calcavecchia estimated where his ball had been when O’Meara’s tee shot moved it, and he placed the ball on that spot.

In the third round, Lance Ten Broeck’s tee shot on the par-4 15th hole struck and moved the ball of Jay Haas already in the fairway. Haas had the same problem Calcavecchia had in the first round, he didn’t know exactly where he was supposed to replace his ball. Again, Rule 20-3c (Placing and Replacing; Spot Not Determinable) provided the procedure that Haas should follow to replace his ball. “If it is impossible to determine the spot where the ball is to be … replaced…through the green, the ball must be dropped as near as possible to the place where it lay but not in a hazard or on a putting green.” Haas estimated where his ball had been when Ten Broeck’s tee shot hit and moved it and dropped the ball as near as possible to that spot, not nearer the hole.

Why did Calcavecchia get to place his ball and Haas have to drop his? The answers are different because of where the balls were on the course when they were moved. When a ball is dropped, it usually comes to rest somewhere other than where it first strikes the course. On putting greens, where there is little or no difference between the lie of a ball in one position or another, the Rule-makers want the ball to be located as near as possible to where it was estimated to have been when it was moved. Therefore on putting greens, balls are placed. Everywhere else on the course, when a ball at rest is moved and the original position of the ball is not known, another thing that is also not known is what the lie of that ball was like before it was moved. Therefore, the Rules require such a ball to be replaced by estimating the spot where it had been and then dropping it so the resulting lie of the ball will be determined by chance, just as it is when it comes to rest after a stroke.

For more information on the Rules of Golf, go to the Rules of Golf page at or watch the Rules of Golf Explained videos at

Written by David Staebler, director of Rules Education for the USGA. Email him at


<< March 2015 >>
Sun Mon Tue Wed Thu Fri Sat
1 2 3 4 5 6 7
8 9 10 11 12 13 14
15 16 17 18 19 20 21
22 23 24 25 26 27 28
29 30 31        




Recent Posts

Partner Links
AmEx image
AmEx image
AmEx image
AmEx image

The USGA and Chevron have committed to using the game of golf to encourage students in science, technology, engineering and math (STEM) disciplines. This commitment has led to the creation of extensive golf-focused STEM teaching tools, and has resulted in charitable contributions to support golf-related programs through Eagles for Education™

At U.S. Open Championships the Chevron STEM ZONE™ is an interactive experience highlighting the science and math behind the game of golf through a variety of hands-on exhibits and experiments.

The partnership has also produced educational materials such as the Science of Golf video series and a nationally-distributed newspaper insert which are provided to teachers as tools to enhance existing curriculum in schools. These lessons teach the science behind the USGA’s equipment testing, handicapping, and agronomy efforts.

For more interactive experiences featuring golf-focused STEM lessons, visit the partnership homepage.

Chevron image

Rolex has been a longtime supporter of the USGA and salutes the sportsmanship and great traditions unique to the game. This support includes the Rules of Golf where Rolex has partnered with the USGA to ensure golfers understand and appreciate the game.

As the official timekeeper of the USGA and its championships, they also provide clocks throughout host sites for spectator convenience.

For more information on Rolex and their celebration of the game, visit the Rolex and Golf homepage.

Rolex image

IBM has partnered with the USGA to bring the same technology, expertise, and innovation it provides to businesses all over the world to the USGA and golf's national championship.

IBM provides the information technology to develop and host the U.S. Open’s official website,, as well as the mobile apps and scoring systems for the three U.S. Open championships. These real-time technology solutions provide an enhanced experience for fans following the championship onsite and online.

For more information on IBM and the technology that powers the U.S. Open and businesses worldwide, visit

AmEx image

Lexus is committed to partnering with the USGA to deliver a best-in-class experience for the world’s best golfers by providing a fleet of courtesy luxury vehicles for all USGA Championships.

At each U.S. Open, Women’s Open and Senior Open, Lexus provides spectators with access to unique experiences ranging from the opportunity to have a picture taken with both the U.S. Open and U.S. Women’s Open trophies to autograph signings with legendary Lexus Golf Ambassadors in the Lexus Performance Drive Pavilion.

For more information on Lexus, visit

AmEx image
American Express

Together, American Express and the USGA have been providing world-class service to golf fans since 2006. By creating interactive U.S. Open experiences both onsite and online, American Express enhances the USGA’s effort to make the game more accessible and enjoyable for fans.

For more information on American Express visit

AmEx image