Jason Day has parted way with caddie Steve Williams, effective immediately.
Former world No.1 Day missed the cut at the opening PGA Tour play-offs event, The Northern Trust, and afterwards the Australian and New Zealander Williams agreed to terminate their partnership.
Williams caddied for Day in six events since June's US Open, missing the cut in two of them including the British Open, with just one top-10 result.
"Parting with Steve was a mutual decision and not an easy one to make," Day told AAP on Sunday.
"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.
"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."
A former caddie for Greg Norman, New Zealander Williams was on the bag for 13 of Tiger Woods' 15 major victories and also carried the clubs for Adam Scott when he became the first Australian to win the Masters at Augusta National in 2013.