Golf - World number one Johnson pulls out of U.S. Masters

By Steve Keating

AUGUSTA, Georgia (Reuters) - World number one Dustin Johnson pulled out of the U.S. Masters on Thursday after sustaining a back injury in a freak fall.

The American, favourite to win the title after victories in his last three tournaments, slipped on stairs in his rental house on Wednesday sparking immediate speculation he would miss the year's first major.

The guessing game continued right up until the moment Johnson appeared on the first tee with playing competitors Bubba Watson and Jimmy Walker then walked away without taking a shot.

Johnson arrived at Augusta National around mid-day and warmed up under the watchful eye of swing coach Butch Harmon.

The situation appeared dire as Johnson took a few cautious swings.

The big-hitting American was in clear discomfort unable to bend over leaving his caddie to tee up his ball.

With his 2:03 tee time approaching Johnson was in deep discussion with his team on the practise range and told a television reporter he was going to give it a try.

A grim-faced Johnson made his way to the first tee but after a few swings turned and walked to the clubhouse.

It was later announced he was withdrawing from the tournament.

The last number one to miss one of golf's majors due to injury was Rory McIlroy at the 2015 British Open and before that Tiger Woods at the 2014 Masters.

(Editing by Ed Osmond and Louise Ireland)