Rory McIlroy out of Bridgestone Invitational defence though injury
Doubts over Rory McIlroy playing in the US PGA have increased after the injured world number one withdrew from next week's WGC-Bridgestone Invitational.
The Northern Irishman. who ruptured an ankle ligament earlier this month, is the defending champion in both events.
Medical experts suggested the 26-year-old could face three months out and he confirmed on Wednesday that he would not compete at Firestone Country Club.
The year's fourth and final major is held a week later at Whistling Straits.
McIlroy sustained a "total rupture" of the anterior talofibular ligament in his left ankle while playing football with friends on 4 July.
The four-time major winner was forced to miss the Scottish Open and the defence of his Open title at St Andrews.
"Unfortunately, I will not be defending my World Golf Championships-Bridgestone Invitational title," McIlroy said in a statement from tournament organisers on Wednesday.
"Best of luck to all the competitors and I look forward to returning to Firestone in 2016."