Australia's Jason Day and caddie Steve Williams ended their partnership after just six tournaments.
"Parting with Steve was a mutual decision and not an easy one to make," Day said, per Sky Sports.
The breakup follows Day's missed cut at The Northern Trust last weekend in Jersey City, N.J.
"He is the ultimate pro. It was a real learning experience being exposed to a caddie who has achieved what Steve has. He has worked with the best," Day said. "But it was a disconnect of old school and new school. Steve has become a friend and I have a lot of respect for him. I thank Steve for everything he taught me."
Williams, 55, rose to fame as the longtime caddie for Tiger Woods. He was on the bag for 13 of Woods' 15 major titles and has also worked with Adam Scott, Greg Norman and Ray Floyd.
Day, 31, is ranked No. 21 in the world and No. 50 in the FedEx Cup standings heading into this week's BMW Championship in Medinah, Ill.
--Field Level Media