Perhaps the shiftiest sand trap in recent major history is now covered up by a hospitality area.

The "Dustin Johnson bunker" will be a memory when the PGA Championship returns this week to Whistling Straits in Wisconsin for the first time in five years.

But countless other sandy areas at the links-style course overlooking Lake Michigan remain hazards — or are they?

"I think the players are much more aware of what they can and cannot do in sandy areas," Rory McIlroy said during a visit to the course in June.

Not knowing the rule proved damaging for Johnson in 2010.

He was assessed a two-shot penalty on the final hole after grounding his 4-iron in the sand to the way right of the fairway, not aware he was in a bunker. He had a one-shot lead when he teed off from the 18th hole.

Johnson missed a 7-foot par putt to slip into a playoff — until he learned he had let his club touch the sand during his pre-shot routine. The two added shots dropped him to fifth.

"I won't be grounding my club anywhere if I miss the fairway, that's for sure. I just missed the memo where all sand is deemed a bunker," Johnson said last week.

Johnson has said he didn't look at the rules sheet that had been posted all week in the locker room and on the first tee. Every bunker, the rules stated, was a hazard, even if outside the ropes where the gallery had been standing.

The confusion is understandable. Johnson has recounted how — in addition to fans standing there — he saw a Gatorade bottle and a beer can in the bunker.

As with both the 2004 and 2010 PGA championships at Whistling, all sand will be considered bunkers.

"All areas of the course that were designed and built as bunkers, filled with sand, will be played as bunkers (hazards) whether or not they have been raked," the PGA said in a notice to competitors ahead of this week's championship.

"This will mean that many bunkers positioned outside of the ropes, as well as some areas of bunkers inside the ropes, close to the rope line, will likely include numerous footprints, heel prints, trash and tire tracks during the play of the Championship."

Such irregularities were "part of the game," the PGA said, "and no free relief will be available from these conditions."

The rules will again be posted in the locker room and other pieces of literature for players, said Dirk Willis, Director of Golf Operations at Whistling Straits.

Every group will be accompanied by a rules official, and players can consult that official should a question arise about the estimated 1,000 bunkers.

There will be no question this time around about the bunker that doomed Johnson on 18.

It was so far right off the target line that the spot is now covered over by a viewing area. There was no intent to hide the spot, organizers said, but it was simply part of a broader plan to bring corporate hospitality on to the course.

If the last two championships at the course are any indication, spectators should be in for a treat.

Martin Kaymer won in 2010, beating Bubba Watson in the playoff. Vijay Singh won in 2004, beating Chris DiMarco and Justin Leonard in another playoff.

Wisconsin native Steve Stricker called the Pete Dye course "visually intimidating."

"You just have to pay attention to your lines," Stricker said. "At times, (Dye) makes it seem like there's not any room to hit it ... Once you get it, it's very playable."

The shifting winds add to the challenge, Stricker said: "It doesn't feel like you're in Wisconsin ... It feels like you're in Europe at a British Open."

That might be because Herbert Kohler, the CEO of the Kohler Co., which owns Whistling Straits, wanted a course that resembled the links courses of coastal Ireland and Scotland. The dunes and some architecture on the course were built to resemble Ballybunion in Ireland.

While the dunes were manmade when the course opened in 1998, more grass has grown in some areas since the intent is to keep an unmanicured, natural look.

"They move over time," Willis said. "They're manmade but they're natural sand structures now. If the wind blows them, it moves around."

McIlroy said being cautious is key.

"So I'll always hover my club regardless if it's a waste area or a bunker, McIlroy said, "just to be on the safe side."

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Follow Genaro Armas at http://twitter.com/GArmasAP