SHEBOYGAN, Wis. -- A controversial rules violation marred the final round of the PGA Championship on Sunday and cost Dustin Johnson a spot in a playoff and a possible major title.
Johnson grounded his club in what was deemed to be a bunker before his second shot, leading to a 2-stroke penalty.
That knocked him out of a potential playoff won by Martin Kaymer over Bubba Watson.
It is the biggest rules snafu at a major championship since the 1968 Masters, where Argentina's Robert De Vicenzo signed for a higher score than he had shot during the final round. That meant he had to accept that score, and missed a playoff with Bob Goalby by 1 stroke.
De Vicenzo's famous quote afterward: "What a stupid I am."
Johnson wasn't feeling stupid Sunday, just stunned. Whistling Straits has more than 1,000 bunkers, several of which would normally be deemed "waste areas" in which a player can ground his club.
But a local rule was in play for the championship, stating that all sand areas would be played as hazards.
"I just thought I was on a piece of dirt that the crowd had trampled down," a despondent Johnson said in the locker room afterward. "I never thought I was in a sand trap. It never once crossed my mind that I was in a bunker.
"Obviously I know the rules of golf and I can't ground my club in a bunker, but that was just one situation I guess. Maybe I should have looked to the rule sheet a little harder."
Johnson took a 1-shot lead to the final hole after birdies at the 16th and 17th holes. A par at the home hole meant victory, a bogey a playoff.
A wayward tee shot at the 500-yard par-4 came to rest in a sandy patch well to the right of the fairway.
The area had been trampled down by spectators and was well outside where traditional fairway bunkers would reside. But Whistling Straits is anything but a traditional course. Bunkers dot the property, hence the rule that was posted in the locker room and handed to every player prior to the tournament.
It read:
"All areas of the course that were designed and built as sand bunkers will be played as bunkers (hazards), whether or not they have been raked. This will mean that many bunkers positioned outside of the ropes, as well some areas of bunkers inside the ropes, close to the rope line, will likely include numerous footprints, heel prints and tire tracks during the play of the Championship. Such irregularities of surface are a part of the game and no free relief will be available from these conditions."
Johnson clearly grounded his club before hitting his second shot well left and short of the green. At the time, he thought he needed to get up and down for a par and victory. As it was, he barely missed the par putt and settled for a bogey that would have put him in a three-hole aggregate playoff.
But PGA of America rules officials clearly noticed the violation and approached Johnson before he even left the 18th green.
"We made it the No. 1 item on our local rules sheet simply to explain that all of the bunkers that were designed and build as sand bunkers on this golf course would be played that way," said Mark Wilson, co-chairman of the PGA of America rules committee.
Asked if he felt the rule was fair, Wilson said: "One thing that is true about the game is that generally speaking a principal of the game is to play the ball as it lies and play the course as you find it. ... This is a unique course with unique characteristics and I think the dilemma is ... that it's even harder to say some of these are not bunkers and some of them are because then how do you define those?"
Unfortunately for Johnson, he didn't consult the rules sheet, nor did he give it much thought before hitting his shot. His caddie, Bobby Brown, declined to comment afterward.
"Honestly, I don't think anyone reads the sheet," said Nick Watney, who played in the final twosome with Johnson. "We've played hundreds of tournaments. We get a sheet every week. I feel for him. I've never seen fans in a bunker with a player. That was a little odd.
"I will say this. Dustin was adamant that he did ground his club. And it was on the sheet. ... Man, that's a tough call, though. Guy's first major. Playoff. It's really unfortunate."
Johnson went from 12 under par to 9 under and a tie for fifth place, 2 strokes out of the playoff. He signed for a final-round 73.
In June, Johnson took a 3-stroke lead into the final round of the U.S. Open at Pebble Beach but shot 82 and finished tied for eighth.
As a consolation, Johnson did earn a spot on the U.S. Ryder Cup team, moving up to sixth in the standings to secure one of the eight automatic spots.
Bob Harig covers golf for ESPN.com. He can be reached at BobHarig@gmail.com.