Tiger Woods started the year with high hopes and a clean bill of health. Rory McIlroy was the undisputed No. 1 player in the world, the winner of back-to-back majors and the overwhelming favorite to complete the career Grand Slam at the Masters and expand his trophy case of majors.

The landscape looks so much different going into the final major.

The focus at the PGA Championship, especially at Whistling Straits, starts with the two players who have attracted the most attention in the majors this year — Jordan Spieth because he is winning them, Dustin Johnson because he is not.

They have been atop the leaderboard in 10 of the 12 rounds at the majors.

Spieth sent golf into a frenzy when two months after his wire-to-wire win at the Masters, he won the U.S. Open to become only the fourth player since 1960 to get halfway to the Grand Slam. That came at the expense of Johnson, who had a 12-foot eagle putt on the final hole at Chambers Bay only to three-putt for par and lose by one.

Johnson looked like the man to beat at St. Andrews when he took a 36-hole lead only to implode on the weekend (75-75) while Spieth made a spirited run at a third straight major. Tied for the lead with two holes to play, he finished one shot out of a playoff.

So what to make of the 97th PGA Championship when it starts Thursday on the Pete Dye on the Wisconsin shores of Lake Michigan?

Even with his blockbuster year, the 22-year-old Spieth still feels as though he has something to prove.

"I've got a little bit of revenge that I need to get out from having control of The Open Championship with two holes to go and not closing it out," Spieth said. "...It was a tough feeling on the flight home."

Even so, a return to Whistling Straits makes it impossible to ignore Johnson.

Beyond his sheer athleticism and the way he crushes the golf ball, the indelible image from the 2010 PGA Championship was Johnson in the scoring trailer, flipping around the pencil to erase the 5 in he made on the final hole to presumably get into a playoff and changing it to a 7 because of a two-stroke penalty.

Whistling Straits has more bunkers than can be counted, and they cover so much of the links-styled course that spectators are allowed to stand and walk — and even build sand castles — in portions of them. Johnson was on the 18th hole and unaware that he was in one of those bunkers when he set his 4-iron on the stand before the shot. He was docked two shots for grounding his club, and suffered yet another close call.

Johnson is all about looking forward.

"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. There was a Gatorade bottle, a beer can, a cup. People were standing in it," he said. "Generally on a golf course, people are not standing in a bunker."

That particular section of the bunker is now out of play. A viewing area has been placed on top of it.

"There are over 1,000 bunkers on the golf course," said Kerry Haigh, the championship director for the PGA of America. "I have never counted them. I'm told that is the number, and we are planning on playing them exactly the same as the last two times. We will try to notify everyone on multiple occasions.

"What happened in 2010 was an unfortunate situation which brought a lot of attention," he said. "People do remember. Our hope is every player and every caddie remembers."

What also doesn't change is the quality of the field, the strongest among majors. It has 98 of the top 100 players in the world — and that appears to include McIlroy.

The world No. 1 has not played since the U.S. Open because of an injury to left ankle. McIlroy sent another tweet Friday showing him on a private jet with emoticons of the American flag and a golf course. He even retweeted his tee time Thursday with Spieth and British Open champion Zach Johnson. He still hasn't said officially that he will play, perhaps waiting to test his ankle over the weekend.

The bigger question is how he will play. McIlroy has gone nearly two months without competition.

That goes for Woods, too. He was No. 1 in the world in 13 of the 18 times he has played the PGA Championship and was out of the top 10 only once — No. 30 in 2011 in a season marred by injuries. Now he will be at best No. 271 as he tries to find his game. It's been an intriguing search. Woods has missed the cut in the last two majors, and it wasn't even close.

He is coming off a tie for 18th in the Quicken Loans National, where he went into the weekend just three shots out of the lead before fading.

Spieth, meanwhile, still has a tiny piece of history to chase.

The Grand Slam ended at the home of golf. Still in play is the "American Slam" — no one has ever won the three U.S. majors in the same season. The PGA Championship is a reminder that these chances don't come along very often.