London: Injured world number one Rory McIlroy will not defend his title at next week`s WGC-Bridgestone Invitational and his withdrawal means Jordan Speith could take over the top spot in the rankings if the American wins the event in Akron, Ohio.
The Briton has been out of action since he injured his left ankle while playing soccer with friends earlier this month. The injury ruled him out of defending his British Open title two weeks ago.
"Unfortunately, I will not be defending my World Golf Championships-Bridgestone Invitational title," he said in a statement on the tournament website .
"Best of luck to all the competitors and I look forward to returning in 2016."
His win at the Firestone Country Club last year carried him to world number one, a standing he could lose if Spieth is triumphant in the tournament that runs from August 5-9.
Four-time PGA Tour winner American Chris Kirk has also withdrawn. He broke his right hand prior to The British Open while playing with his children.