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 a career Grand Slam at the Masters.

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

The focus at the PGA Championship, especially at Whistling Straits in Sheboygan, Wisconsin, starts with the two players who have attracted the most attention in 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.

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 only to three-putt for par and lose by one.

Johnson looked like the man to beat in the British Open 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 left, he finished one shot out of a playoff.

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

Even with his blockbuster year, Spieth, 22, still feels 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 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 numerous bunkers, 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 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.

Now he’s 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 aren’t standing in a bunker.”

That particular section of the bunker is 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’s the number and we’re 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, and that appears to include McIlroy.

He hasn’t played since the U.S. Open because of a left ankle injury. 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 hasn’t said officially that he’ll play, perhaps waiting to test his ankle over the weekend.

The bigger question is how he’ll play. He’s 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’s 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’ll 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’s coming off a tie for 18th in the Quicken Loans National, where he went into the weekend three shots out of the lead.

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 won the three U.S. majors in the same season.