The US Open - the second major of the year which McIlroy won in 2011 - begins on June 15.
Northern Ireland's Rory McIlroy has pulled out of his last warm-up event for the US Open, saying he would skip the US PGA's Memorial with lingering rib trouble.
The injury, which McIlroy suffered in the off-season, flared up at the Players Championship two weeks ago and prompted him to miss this week's European PGA Championship at Wentworth.
An MRI exam after the Players showed no new injury, and McIlroy's agent Sean O'Flaherty told the BBC that for the world number two "all focus is on getting back to full health for the US Open".
The US Open - the second major of the year which McIlroy won in 2011 - begins on June 15 at Erin Hills in Wisconsin.
McIlroy has missed the Memorial, hosted by 18-time major champion Jack Nicklaus, only once in the last seven years.