By Mark Lamport-Stokes
KOHLER, Wisconsin (Reuters) - If any extra proof was needed that this week's U.S. PGA Championship at Whistling Straits is wide open for the taking, then look no further than the winners of the last two majors.
With Tiger Woods a shadow of his former dominant self, Britain's Graeme McDowell made his major breakthrough in the U.S. Open at Pebble Beach and South African Louis Oosthuizen followed suit in last month's British Open at St. Andrews.
Professional golf has never enjoyed greater strength in depth and, with top-ranked Woods immersed in one of the biggest slumps of his career, unpredictability is once again sure to be the watchword at Whistling Straits.
Add to that the struggles of world number two and 2005 PGA champion Phil Mickelson in the final round of the WGC-Bridgestone Invitational on Sunday, and you have the recipe for an intriguing menu at the year's final major.
"When you have one player dominating and winning consistently, very few people are gaining confidence. If anything, it's going to work in the opposite way."
Woods, comfortably the leading player of his generation and a 14-times major winner, has not triumphed on the PGA Tour since the BMW Championship last September.
Although he has clinched the PGA Championship four times, most recently in 2007, even his strongest backers will feel wary this week based on his fluctuating fortunes this season.
Since he became embroiled in scandal following revelations about his serial philandering at the end of last year, he has lost the aura of invincibility he once held over his rivals.
Winless in eight starts on the 2010 PGA Tour, Woods plunged to new depths at Firestone last week when he produced his worst ever finish on the U.S. circuit.
A closing 77 left him tied for second-last in the 80-player field, raising questions over the state of his mind going into Whistling Straits with a divorce reportedly imminent.
"(I'm) just not playing well," Woods said stone-faced after producing his highest 72-hole aggregate on the PGA Tour and his worst relative to par. "It's been a long year."
Left-hander Mickelson fared even worse on Sunday, battling to a closing 78 when a strong finish would have helped him claim the world number one ranking for the first time.
These are certainly very interesting and unpredictable times in professional golf, making this week's PGA Championship at least as unpredictable as any which have preceded it.
Ninety-seven of the world's top 100 players will be assembled at Whistling Straits for Thursday's opening round and you can bet that at least a handful will go on to deliver their 'A' games in pursuit of the season's last shot at major glory.
"The strength and depth now is very, very strong. Guys like Louis Oosthuizen, I've played with him a few times and you're always staggered by how well he swings it, how well he hits the ball."
Remarkably, there have been five first-time winners in the last six majors with Mickelson's emotional victory at the U.S. Masters in April the sole exception.
Lucas Glover won the 2009 U.S. Open, fellow American Stewart Cink clinched the British Open the following month and South Korean Yang Yong-eun became Asia's first male major winner when he overhauled Woods to land last year's PGA.
Whistling Straits has once before staged the PGA Championship, in 2004 when Vijay Singh emerged triumphant after a three-way playoff on the longest course to stage a major.
Although a few yards shorter this year, the par-72 layout modeled on an Irish seaside links will once again provide a stiff test with its soaring sand dunes, fast-running fescue fairways and deep pot bunkers.
Of all the majors in recent times, the PGA attracts the strongest field and yet it has often been the most likely to throw up a surprise winner.
Whoever ends up lifting the prized Wanamaker Trophy on Sunday will have coped best with one of golf's toughest challenges.
(Editing by Frank Pingue)