Jason Day's partnership with caddie Steve Williams was short-lived.
After missing the cut at The Northern Trust at Liberty National Golf Course this past weekend, Day told the Australian Associated Press that he has parted ways with Williams, who has carried his bag since the U.S. Open in June.
"Parting with Steve was a mutual decision and not an easy one to make," Day told AAP. "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."
Day's agent, Bud Martin, also confirmed the change to ESPN on Monday.
According to the AAP, Day will have friend and fellow pro David Lutterus on his bag at the BMW Championship at Medinah this week.
Day lured Williams out of retirement the week before the U.S. Open. Williams was on Tiger Woods' bag for 13 of his 15 major championships. Williams also worked with Greg Norman, Raymond Floyd and Adam Scott. Day had been using a combination of friends to caddie for him over the past two years.
"I am very disappointed with how this year's progressed," Day said at the time. "I didn't play well, and I need to improve that. And I need to start working harder, and that's plain and simple.
"And that started with -- this is no disrespect to my mates that were on the bag. They were very, very hard workers. They were great. But I think Steve will take me to that level and I'm hoping that's the case."
Day had a promising start with Williams. He finished tied for 21st at the U.S. Open at Pebble Beach and tied for eighth at the Travelers Championship the next week. But then he missed the cut in two events, including an epic meltdown at the Open Championship, and didn't finish better than a tie for 40th at the no-cut WGC-FedEx St. Jude Invitational in Memphis.
Day, a former world No. 1, has fallen to 50th in the FedEx Cup standings and will have to play well at this week's BMW Championship to advance to the season-ending Tour Championship at East Lake Golf Club in Atlanta.
Day is in ninth place in the International Presidents Cup standings. Only the top eight players in the standings are guaranteed spots on captain Ernie Els' team. Els will also make four captain's selections for the Dec. 9-15 event at Royal Melbourne Golf Club in Day's native Australia. Players can accumulate points through the BMW Championship.