Mike Cormack

Dustin Johnson listens as PGA rules official David Price informs him he made a boo-boo.

Dustin Johnson’s miscue at the PGA is a perfect example of how your mind can be as important as your swing.

If Dustin Johnson is still looking for someone to blame following the PGA Championship, he should look in the mirror.

As we watched the incredible conclusion at Whistling Straits unfold, we couldn't help but think of Roger Maltbie.

At the conclusion of his weekly feature, "The Rules of Golf" during NBC golf telecasts, the on-course reporter and former PGA Tour player always ends his segments with the following reminder: "If you play this game, you gotta know the rules."

Johnson can now fully expect to be featured in a future segment.

Say what you will about the PGA of America designating random patches of sand "bunkers," the lack of crowd control on the 18th hole, or the inability of a rules official to warn Johnson before he grounded his club, had he been thinking clearly Sunday's two-man playoff would have been three.

As we have since learned, players were informed of the unique bunker rules at Whistling Straits prior to the tournament. So Johnson either failed to read them, or the pressure of playing the final hole of a major championship with a one-shot lead caused a major brain cramp.

He is not alone.

Golf history is littered with major championships that have been won and lost between the ears as much as they were on the course.

Jesper Parnevik at the '94 Open Championship, Jean Van de Velde at the '99 Open Championship and Phil Mickelson at the '06 U.S. Open are just three recent examples.

They are the ultimate reminder that the mind can be the 15th club in the bag.

Upon reaching his ball off the 18th tee, a clear-thinking Johnson would have called for an official to clarify his lie, but instead he chose to do what comes naturally to him -- play the shot quickly -- and the results were disastrous.

Johnson's quick trigger also cost him dearly at the U.S. Open in June, when he rushed several shots on the second hole on Sunday en route to a triple-bogey 7 and a final round 82.

To his credit, he showed great fortitude to contend last week, but unless the big-hitting American can find a way to ease off the gas pedal while under pressure the game's top prizes will continue to elude him.

Who is Sean Foley?

Jaime Diaz tries to answer the question in this Golf Digest profile. While it seems almost inevitable that the Toronto native will become Tiger Woods' next swing coach, Diaz wonders whether Foley's brash personality can mesh with the private world No. 1 long-term.