Martin Kaymer has dropped caddie Craig Connelly just three months since the German became the world's best player.
Kaymer's brother will be on his bag at this week's Volvo World Matchplay in Spain.
Connelly was on the bag when Kaymer won the US PGA at Whistling Straits last summer, as well as the German’s ascension to world No. 1.
“Had fantastic year with Craig winning the PGA & Race to Dubai. He’s a good caddie & nice guy. Just felt it was time for a change,” Kaymer said.
Kaymer has since slipped to third behind Westwood and Luke Donald after he missed the cut in The Masters for the fourth year running.
Kaymer, who will not be short of people wanting to step into Connelly's shoes, said he was unsure when a full time replacement would be appointed.
But for now he will be accompanied by his brother, a law student who worked as Kaymer's caddie in his rookie season.
"I haven't had any calls yet (from other caddies) - I think nobody knows," Kaymer continued. "But obviously now some people will know."
"I'll just try to have some fun with him this week and we'll see what happens at Wentworth if I find somebody.
"If not, I'm sure I will find somebody for the US Open."
This week's event at Finca Cortesin in Andalucia is second only to The Open in Europe this year with a first prize of almost £700,000.
Fanny Sunneson, who has been a mentor to Kaymer, will not leave the bag of Henrik Stenson to support Kaymer.