Expect the unexpected at next week's Augusta Masters

As the first of the season's four major championships, the Masters has always been the most keenly anticipated, a veritable golfing 'rite of spring' that brings together the game's leading players in Augusta, Georgia.

This year, that sense of expectation is especially heightened with the list of likely winners deeper than ever and multiple champion Tiger Woods a notable absentee for the first time in his career after having surgery to repair a pinched nerve in his back.

Fellow American Phil Mickelson, another perennial contender at Augusta National, is also facing injury concerns of his own, leaving golf fans to expect even more of the unexpected as the April 10-13 tournament fast approaches.

Woods, who has claimed the coveted Green Jacket four times, has struggled with back pain since last August and he withdrew from last month's Arnold Palmer Invitational, his final tune-up event, to get ready for the Masters before that bid was aborted.

"This is frustrating, but it's something my doctors advised me to do for my immediate and long-term health," said Woods.

Mickelson has won three times at Augusta National, most recently in 2010, but his preparations for the year's opening major were rocked when he pulled out of last week's Texas Open during the third round with a pulled abdominal muscle.

"My back's feeling great, my body's been feeling great. I felt as good as I have all year," said the left-hander, whose decision to withdraw seemed purely precautionary. "My speed is back, I was hitting the ball hard, driving it great.

"I pulled a muscle on my downswing trying to hit the ball hard ... it just killed and it wouldn't subside for 10 or 12 seconds ... there's really not much you can do for a pulled muscle. I hope I'll be OK."

Whether or not Mickelson is a significant factor next week, the possibilities are seemingly endless when it comes to likely winners after Sunday's final round.

The last seven editions have produced seven different champions and golf's extraordinary depth of talent has been showcased on the 2013-14 PGA Tour where there have been 17 different winners from the 20 tournaments so far completed.

"Everybody that tees it up here is a great player," said American Matt Kuchar, who was tied for the lead with nine holes remaining at the Texas Open on Sunday before finishing two strokes behind the triumphant Steven Bowditch.

Australian Bowditch came into the event ranked 339th in the world but survived a windswept final round with a four-over-par 76 at the TPC San Antonio to clinch his first victory on the U.S. circuit.

"It's not as if there's (former tennis world number one) Roger Federer going up against somebody you haven't heard of," said Kuchar. "It's a lot different in golf.

"The guys that play really good quality golf from top to bottom are the kind of guys that enter the tournament (any PGA Tour event), so it's tough. You know that you got to play great to win out here."

Short game wizardry and the ability to minimise three-putts are musts for any would-be Masters champion at an iconic venue renowned for its lightning-fast, heavily contoured greens.

The list of potential champions next week is a long one, as demonstrated by the 'unlikely' Masters victories of Canada's Mike Weir in 2003, American Zach Johnson in 2007 and South African Trevor Immelman in 2008.

Twice major winner Rory McIlroy will be eager to atone for his nightmarish final-round meltdown three years ago when he squandered a four-shot overnight lead with a closing 80.

The Northern Irishman will also be champing at the bit to prove that his struggles on and off the course for much of his 2013 campaign are now behind him, and his form so far this year has been encouraging.

McIlroy, 24, earned himself a timely boost with his victory at the Australian Open in December and this season he has been in title contention in five of the six strokeplay events he has entered.

Back-to-back Masters victories have been rare with only three players accomplishing the feat since the tournament was launched in 1934. Jack Nicklaus was the first to do so in 1966, and he was followed by Nick Faldo, in 1990, and Woods, in 2002.

Defending champion Adam Scott of Australia will have a good opportunity next week to add his name to that illustrious company, having climbed to number two in the world rankings with a superb run of form late last year.

He clinched his 10th PGA Tour title at The Barclays in August before ending his season by winning the Australian PGA and Australian Masters, partnering Jason Day to land the World Cup team event and finishing second at the Australian Open.

Though Scott has not triumphed since, he has recorded three top-10s in his last five PGA Tour starts and will tee off in Thursday's opening round at Augusta National among the title favourites.

"The work I'm putting in keeps me up there (contending) on a more regular basis," said Scott, who became the first Australian to win the Masters by edging out Argentina's Angel Cabrera in a thrilling playoff.

"It's been an incredible experience being the Masters champion for the last 12 months, and it's something I'll be trying to do again."