According to @SiriusXMPGATOUR's Jason Sobel, Rory McIlroy was forced into a late driver change prior to the PGA Championship's first round on Thursday.
As just reported on @SiriusXMPGATOUR:Rory McIlroy’s “gamer” driver was deemed non-conforming by the USGA on Tuesday. He switched drivers prior to yesterday’s opening round.May 16, 2025
In a tweet, Sobel wrote: "Rory McIlroy’s “gamer” driver was deemed non-conforming by the USGA on Tuesday. He switched drivers prior to yesterday’s opening round."
As of writing, it's unclear as to why the 36-year-old's driver was non-conforming, but some reports have claimed the club failed a CT (characteristic time) test, whereby it measures the spring-like effect of a club face.
The test works via a small, pendulum device that strikes the clubface with a metal ball and, currently, there has been no official announcement by either the PGA or USGA as to why the driver failed the test.
McIlroy's driver of choice is the TaylorMade Qi10 and, at the PGA Championship, it hasn't been behaving as well as we are used to seeing.
For example, McIlroy hit just four of 14 fairways on Thursday, with the recent Masters winner ranking 85th in terms of Strokes Gained: Off The Tee and 41st in Driving Distance.
On Friday, those stats did improve, but weren't anywhere near the levels we are used to seeing from McIlroy, who battled back valiantly to get inside the cutline at Quail Hollow.
The report prompted to the PGA of America to release a statement, which explained why results of the testing are kept "confidential.“
"We can confirm that the USGA was invited to do club testing at the PGA Championship, at the PGA of America’s request," Kerry Haigh, Chief Championships Officer, PGA of America, said.
"That testing program is consistent with the same level of support that the USGA provides to the PGA Tour and other championships, as part of their regular programs for driver testing.
"The standard process is for about a third of the field to be randomly tested under the program. That was the case at Quail Hollow this week. Finding driver heads that have crept over the line of conformance is not an unusual occurrence, especially for clubs that are hit thousands of times over a long period of time.
"The results are kept confidential to protect players, who are unaware the club has fallen out of conformance and not responsible for it falling out of conformance other than hitting the club thousands of times.
"Players are simply asked to change heads if necessary, and all do without issue. To publicly identify players whose club did not conform can lead to that player being questioned unnecessarily.
"Neither the USGA nor the PGA of America have any concerns about player intent.”
