AUGUSTA, Georgia (AFP) - World No. 1 Dustin Johnson was uncertain to play as the 81st Masters began on Thursday (April 6), swirling winds adding a new twist to an epic showdown at Augusta National.
Northern Ireland's second-ranked Rory McIlroy could be the man who benefits most if Johnson, scheduled for an afternoon tee-off, eventually decides to withdraw after hurting his back in a fall at his rented house on the eve of the tournament.
Australian world No. 3 Jason Day is also among the top rivals expected to challenge for the title along with 2015 Masters champion Jordan Spieth.
Johnson suffered a serious fall on a stairway, according to his agent, but is still hoping to take part in the tournament.
He was expected to visit the PGA Tour's medical trailer on Thursday morning for possible X-rays or an MRI exam on his lower back.
The world No. 1 is the odds-on favorite for the Masters after winning three events in a row in a faultless buildup to the first men's Major tournament of the year.
But McIlroy, another long-hitter like the 32-year-old Johnson, is seen as a serious threat.
In his ninth Masters, he is seeking to complete a career grand slam at Augusta and hoping to make amends for a Sunday back-nine disaster that cost him the title in 2011.
American Daniel Summerhays struck the first tee-shot on hole No. 1, the par-four, 445-yard dogleg know as the Tea Olive, at 8am to launch the tournament on a course rain-soaked from overnight thunderstorms.
Cold and windy conditions, with gusts of up to 65kmh, were expected to play havoc with the world's greatest shotmakers for the first two days of the 72-hole showdown.