Phil Mickelson has split from coach Butch Harmon after eight years together, a spell which included two of the left-hander's five Major wins.
Mickelson flew to Las Vegas last week to tell Harmon in person and now the pair have released a joint statement explaining the move.
"Butch Harmon is one of the great teachers in the history of the game and I believe he deserves to be in the World Golf Hall of Fame,” said the left hander.
"I've learned a great deal from him in our eight years together. It's just that at the moment I need to hear new ideas from a different perspective."
Mickelson won the 2010 Masters and 2013 Open Championship under Harmon, but the victory at Muirfield is his last to date and the 45-year-old has recorded just five top-10 finishes since.
One of those came at Augusta National in April, where he finished joint second behind Jordan Spieth, but he was not a factor in any of the year's other majors.
He needs to win the US Open to complete a career grand slam, though a sign of his recent slump is his failure to qualify for the season-ending Tour Championship for the second season in succession.
"I've thoroughly enjoyed working with Phil and we've had great success together," added Harmon.
"Helping him win the Open Championship in 2013 was one of the pinnacles of my career. I see nothing wrong with him seeking advice from another source. We're great friends and always will be."
Harmon made his name as Tiger Woods’ coach, helping him to eight of his 14 majors, though there was a bitter split.
