Three-times major champion Phil Mickelson has switched allegiance to swing coach Butch Harmon in a bid to improve the accuracy of his long game, especially his driving.

Mickelson, who blew a golden opportunity to win last year's US Open at Winged Foot with a wayward tee shot at the last, had previously worked with Rick Smith for most of his career.
   
Although the American left-hander will now spend most of his practice time with Harmon, he plans to retain his close personal and professional ties to Smith.
   
"Butch is one of the very best teachers in the world," Mickelson said in a statement released by his manager on Monday. "He's helped two players rise to number one in the game and I'm fortunate that he has agreed to spend time working with me on my game, particularly on my driving.
   
"We've been friends for years and I'm eager to explore new avenues and implement new ideas with him."
   
Harmon, who helped Greg Norman and Tiger Woods reach the pinnacle of the game, gave Mickelson coaching advice at two PGA Tour events earlier this year when Smith was absent.
   
The pair worked together on the practice range at the WGC-Accenture Match Play Championship in late February and also at last month's WGC-CA Championship.

"This has been a difficult decision for me," said Mickelson, adding that Smith had been "very instrumental" in most of his 30 PGA Tour victories, and particularly his three majors.
   
"I feel that now is the time to go in a new direction with Butch Harmon on my long game. I went to Rick Smith as a friend and asked for his understanding of this decision and he's been very supportive of it. No one could ask for a more true or loyal friend."
   
Mickelson, known for his attacking brand of golf, was on the brink of a third successive major victory when he spectacularly fell out of contention for last year's US Open.
   
Despite poor driving for most of the final round, the American's scrambling abilities kept him in the title hunt before he surrendered a one-shot lead with one hole to play.
   
He unleashed a wild drive off the 18th tee that bounced off the roof of a hospitality tent and into the crowd, then struck a tree with his second shot before running up a double-bogey six and handing the tournament to Australian Geoff Ogilvy.
   
More meticulous than most of his peers in preparing for majors in recent years, Mickelson had been working hard with Smith to eliminate the errant tee shot to the left, the wayward push or fade.
   
Stung by his Winged Foot experience, he has repeatedly said his main focus has been to "fix" his driving.
   
Smith, an integral component of 'Team Mickelson' along with short game guru Dave Pelz, said: "I think it is a good time for Phil to get a different perspective.
   
"Butch has been a friend of mine for years and we have a mutual respect for one another. In the end, I truly want what is best for Phil's success."