Rory McIlroy will miss next week's BMW PGA Championship at Wentworth due to an on-going rib injury.
The world number two suffered the problem in the off-season after hitting a lot of balls in practice trying to decide on new equipment after former supplier Nike decided to stop producing clubs last year.
It flared up as he lost a play-off to Graeme Storm at the BMW SA Open in January and he did not feature again until the WGC-Mexico Championship in March where he finished four shots behind winner Dustin Johnson.
The Northern Irishman resumed an active schedule but felt discomfort at the Players Championship and despite a scan revealing he has suffered no new injury, he will not now tee it up at the European Tour's flagship event on Thursday.
"Having had a reaction to my earlier rib injury, I have been advised to take a conservative approach to my recovery which unfortunately means I have to withdraw from the BMW PGA Championship next week," said McIlroy.
"It's a disappointing decision to have to make but I have to ensure I make a full recovery. I will now continue the process of preparing my game for the US Open and the rest of the season."
McIlroy, 28, is a previous winner at Wentworth, with his victory in 2014 kicking off a brilliant summer that saw him claim the Open Championship, the US PGA Championship and WGC-Bridgestone Invitational.
European Tour chief executive Keith Pelley said: "There is no question that Rory will be missed at the BMW PGA Championship but his health is the most important thing and we wish him a speedy recovery."