After 25 years, Phil Mickelson and his caddie Jim ‘Bones’ Mackay are going their separate ways.

It is not known what prompted the split but the pair each released a statement saying there was still good will between them and it was a “mutual” decision.

"Player-caddie relationships don't often last that long," Mackay said in his statement. "I wish Phil nothing but the best. His game is still at an elite level, and when he wins in the future (definitely the Masters), I will be among the first to congratulate him."

Arguably the most-recognised player-caddie teams in golf, Mickelson and Mackay began working together at a US Open sectional qualifier in 1992.

Since then they have combined for five major championship wins and 49 worldwide professional titles. Their last win together was the 2013 Open Championship at Muirfield.

“After 25 very rewarding and memorable years, Bones and I have mutually decided to end our player-caddie relationship,” Mickelson said in his statement. "Our decision is not based on a single incident. We just feel it's the right time for a change.

"My relationship and history with Bones far exceeds golf. He has been one of the most important and special people in my life since the day we met and I will always be grateful for everything he has done for me.

“Bones is one of the most knowledgeable and dedicated caddies in the world. He is always prepared and has the ability to make decisions in pressure-packed situations. Bones is without a doubt one of the most thoughtful people that I have ever known. The next player to work with him will obviously be very lucky.”

Mickelson also confirmed his brother, Tim, will caddie for him for the remainder of 2017 season.

The duo worked well together even if they didn't always see eye-to-eye. PHOTO: Getty Images.

Mackay, who had a double-knee replacement last October, made no mention of his future plans but said his 25 years on Mickelson’s bag had been a privilege.

“I will always be grateful that I was around to witness so much of Phil’s career. When Phil hired me in 1992, I had one dream: to caddie in a Ryder Cup. Last year, at Hazeltine, Phil played in his 11th straight Ryder Cup. It was so cool to have a front row seat,” Mackay said.