Georgia - Lee Westwood and Matt Kuchar won last week, each ending four-plus years without winning on their home circuit. They also won without their regular caddies.
Kuchar used a local caddie at Mayakoba because he entered at the last minute and his regular looper, John Wood, had a previous engagement. Westwood used his girlfriend, Helen Storey, who previously caddied for him in Denmark.
Wood is back to work with Kuchar this week at the Australian Open. Billy Foster's 10-year run with Westwood is done.
"Mine and Billy's working relationship had got to a point where neither of us were gaining anything from it and we weren't doing each other any good," Westwood said on Tuesday at the DP World Tour Championship in Dubai.
"I sat him down and said, 'This is no good, I'm playing better when you're not there than when you are there, so something's obviously not working.' He said to me, 'Well, I can't caddie for you how I want to caddie for you.'"
Westwood said he has reached a stage in his career where he doesn't need as much from his caddie, and he felt Foster wasn't happy just carrying the bag.
"It just was one of those things that had to come to an end," Westwood said.
"We've obviously had a great time the last 10 years and been very successful, but people change and the way you work and look at things."
Foster is working with Matt Fitzpatrick in Dubai. Westwood is using South African Glen Murray, who was on the bag with Sergio Garcia when the Spaniard won the Masters in 2017.