Heading into the weekend, it was reported that McIlroy had to switch out his driver because his regular driver was deemed non-conforming to USGA standards. While the PGA and USGA dismissed that anything nefarious was behind a non-conforming test result, McIlroy's absence for four consecutive days of media was not a great look for him.

The Northern Irishman went from favorite at Quail Hollow to struggling off the tee. It might be more than a coincidence.

Rory McIlroy left the PGA Championship without a single word to the media on Sunday, leaving the golf world none the wiser as to the details of the reported failure of his driver to pass a conforming test earlier in the week.