The USGA tested Rory McIlroy's driver and concluded that it did not meet established standards, forcing him to change it before the PGA Championship.

Rory McIlroy will be forced to use his backup driver at the PGA Championship after his preferred driver was deemed “non-conforming” by the USGA. The discovery came after the USGA did testing at Quail Hollow at the request of PGA of America,

Rory McIlroy is one of the best drivers of the golf ball of his generation, but has been wayward off the tee at the PGA Championship after being forced to change driver