World number two Rory McIlroy has withdrawn from next week's PGA Championship at Wentworth because of a rib injury.
The 28-year-old, who was treated for a stress fracture to his ribs earlier in the year, felt discomfort during the recent Players Championship in Florida.
"I have been advised to take a conservative approach to my recovery," said McIlroy.
"It is disappointing, but I have to ensure I make a full recovery."
McIlroy won the European Tour's PGA Championship at the Surrey course in 2014.
The four-time major winner said he would now concentrate on preparing for the US Open in June.
McIlroy originally suffered the rib problem in the off-season after hitting a lot of balls in practice as he tried to decide on new equipment after Nike decided to stop producing clubs.
It flared up as he lost a play-off to Graeme Storm at the South African Open in January, and he did not feature again until the WGC-Mexico Championship in March, when he finished four shots behind winner Dustin Johnson.
The Northern Irishman then felt discomfort at the Players at Sawgrass.