Phil Mickelson has decided to bring to an end his 25-year partnership with his caddie Jim 'Bones' Mackay.

With Mackay in tow, Mickelson won five Majors and a staggering 41 PGA Tour titles. It's a big surprise that the two have decided to part company.

According to Mickelson, the separation was mutual and from now on, his brother Tim will act as his caddie.

Speaking of his decision to part ways with Mackay, Mickelson explained that it was not a conclusion they came to lightly.

"Our decision is not based on a single incident. We just feel it's the right time for change. Bones is one of the most knowledgeable and dedicated caddies in the world," Mickelson said, as per BBC Sport.

Mickelson clearly has a great deal of respect for Mackay and has said whoever lands Bones as their caddie next, will feel extremely grateful.

"The next player to work with him will obviously be very lucky. 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".

Despite the mutual decision to part company, it feels like an odd move from Mickelson and Mackay, who shared great success together over the years.

Indeed, since working with Mackay, Mickelson won over $80 million in prize money and there aren't many more successful sporting partnerships around.

Speaking of the split, Mackay was quick to commend Mickelson for hiring him in the first place and wished him the best for the future.

"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.

"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."

It will be interesting to see who ends up with Mackay as their caddie, and it will be equally fascinating to see how Mickelson performs with his brother, Tim, as his caddie in the future.

Mickelson fans will be hoping that the split won't affect his game too much, but when long-term sporting partnerships come to an end, there can often be a transitional period - just look at Manchester United.