For the second time this year, Rory McIlroy will miss tournament time due to a rib injury he first suffered when testing equipment, and which he aggravated while preparing for last week's Players Championship.
McIlroy, 28, withdrew Friday from next week's BMW PGA Championship in England, the European Tour's flagship event and one the Northern Irishman won in 2014.
"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," McIlroy said in a statement released by the European Tour. "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 U.S. Open and the rest of the season."
McIlroy, ranked second in the world, was expected to play the Memorial Tournament on the PGA Tour the following week. It is unclear if he will attempt to play at Jack Nicklaus' tournament in Ohio.
The rib injury first surfaced in January prior to McIlroy's first start at the South Africa Open, where he lost in a playoff. Afterward, he was diagnosed with a fractured rib and missed scheduled starts on the European Tour in Abu Dhabi and Dubai, and on the PGA Tour at the Genesis Open and Honda Classic.
He returned at the WGC Mexico Championship, and in five tournament starts he has three top-10s, including a tie for seventh at the Masters. He tied for 35th last week at the Players Championship, where he disclosed that he had some discomfort.
McIlroy said he took three weeks off from golf after the Masters and around the time of his wedding.
"I went back at it again on Friday [May 5], and instead of maybe gradually building up again, I hit balls for four or five hours and did the same on Saturday," McIlroy said. "I felt a bit of stiffness on Sunday, hit a couple of drives, and didn't feel quite right.
"So maybe I should have just taken it a bit easier over the weekend. But I was excited to get back, excited to get ready to play again, and so maybe just being a little overkeen was a detriment."
McIlroy has played six tournaments in 2017. He is the PGA Tour's reigning FedEx Cup champion, having won the Tour Championship last year.