Rules for hitting the wrong ball

Hunter Mahan
USA Today Images
Hunter Mahan accidentally hit Jamie Donaldson's ball during Friday's round of the U.S. Open.
By Mark Aumann

Series: Golf Buzz

Published: Saturday, June 14, 2014 | 11:20 a.m.

Every amateur has probably had that "whoops" moment when they suddenly realize the ball they just hit isn't theirs. But for it to happen on a stage like the second round of the U.S. Open? That's pretty unusual.

But that's exactly what happened Friday to Hunter Mahan and Jamie Donaldson during the second round at Pinehurst No. 2. They use the same brand of ball, and mark their balls in similar fashion. So despite having the assistance of caddies and marshals, they still committed the cardinal sin of playing the wrong ball.

GOLF BALL MIXUP: Mahan, Donaldson penalized for playing wrong balls

So what's the rule -- and the penalty -- for playing the wrong ball? It falls under Rule 15-3b, according to Bryan Jones, co-vice chairman of the PGA Rules Committee. Here's the official definition:

"If a competitor makes a stroke or strokes at a wrong ball, he incurs a penalty of two strokes.

The competitor must correct his mistake by playing the correct ball or by proceeding under the Rules. If he fails to correct his mistake before making a stroke on the next teeing ground or, in the case of the last hole of the round, fails to declare his intention to correct his mistake before leaving the putting green, he is disqualified.

Strokes made by a competitor with a wrong ball do not count in his score. If the wrong ball belongs to another competitor, its owner must place a ball on the spot from which the wrong ball was first played."

MORE RULES QUESTIONS: What do you do if your ball moves at address?

In the case of Mahan and Donaldson, they realized their mistake once they reached the green, so they were able to go back and play the correct ball from the fairway, albeit after taking a two-stroke penalty.

"In stroke play, the concept is to play your ball from the teeing ground into the hole and you can only switch balls as permitted by the Rules," Jones said. "Examples are if you lose your ball, hit it into the water or it becomes unfit for play, then you may substitute a ball. If a wrong ball is played, the player must correct the error by playing the correct ball.

"Since Hunter and Jamie played each other's balls, each was guilty of playing a wrong ball, each needed to add two penalty strokes to their score on the hole and each of them was required to play the correct ball from the correct spot. The stroke played with the wrong ball did not count in Hunter or Jamie's score."

Interestingly enough, Jones said Rule 12-2 -- which allows a player to lift his ball for identification -- might have saved both players the indignity.

"I did not see the incident so I do not know if the balls were close together but the incident highlights another important Rule, Rule 12-2," Jones said. "This Rule allows a player to lift his ball (with a few procedural requirements) anywhere on the golf course.

"Why does Rule 12-2 exist? To help players avoid a wrong ball penalty. Pretty sure Hunter and Jamie regret not implementing it."

Unfortunately, the gaffe may have cost Mahan a shot at making the cut. With the penalty, he finished with a 72, one shot shy of playing on the weekend.