ZACH JOHNSON, the Open champion, has taken a relaxed approach to the rules issue which overshadowed the last US PGA Championship to be played at Whistling Straits.

Dustin Johnson, the 39-year-old's fellow American, was one shot ahead with one to play in 2010 and thought when he missed a six-foot par putt that he would be heading into a play-off with Martin Kaymer and Bubba Watson.

However, Johnson was then penalised two strokes after it was ruled he had grounded his club in a fairway bunker before hitting his second shot.

He later admitted: "I guess it's one situation where I should have looked at a rule sheet."

The rules regarding the bunkers remain the same in 2015, but when asked if he had read any guidance to the players, Zach Johnson said: "I did hear there's something posted next to the urinals, but I have not checked it out yet."

Johnson, who won his second major title in at St Andrews last month, added: "I haven't really studied it or paid much attention to it.

"I think we all kind of know, based on that incident, that better safe than sorry. I think everything is treated as a hazard this week, every piece of sand ... at least that's the way I'm going to treat it, just to be on the safe side."

The spectacular course on the banks of Lake Michigan, where play begins in the last major of the year tomorrow, has more than 1000 bunkers.

But many of them are not easily defined so the rules of play for the week state that: ''All areas ... designed and built as bunkers, filled with sand, 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 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 of surface are a part of the game and no free relief will be available from these conditions. All bunkers inside the ropes will be raked each morning prior to play as normal."