Rory McIlroy's days as one of LIV Golf's most vocal critics may be over.

The four-time major champion demurred on Tuesday when asked to speculate what professional golf might look like down the road.

"I don't have a crystal ball," McIlroy said ahead of the 2023 PGA Championship that begins on Thursday at Oak Hill.

Maybe that's by design. Asked if he was making a conscious effort to sidestep talking about Saudi-funded LIV going forward, McIlroy simply responded, "Yeah."

The world No.3 hardly seems to be alone in taking that approach. Masters champion and No.1 Jon Rahm and the second-ranked Scottie Scheffler essentially shrugged off any LIV talk while getting ready to play 72 holes on the demanding East course.

The white-hot spotlight that followed players from both the PGA and LIV tours to Augusta National in April seems to have cooled a bit.

Maybe it was the fact the only fireworks that erupted at the Masters were limited to the golf course - where LIV's Phil Mickelson was runner-up and Brooks Koepka played in the final group with Rahm - and not press conferences or social media.

McIlroy says his focus is solely on the PGA Championship starting on Thursday after a mid-season reboot by the 34-year-old who took three weeks off to refocus following the disappointment of missing the cut at Augusta.

It was a decision that meant he forfeited $US3 million of his Player Impact Performance earnings for withdrawing from a second designated event.

Twice a winner of PGA Championship, McIlroy appears to still be in a bit of a competitive funk finishing in a tie for 47th in his only start since the Masters.

But he believes he is close to the form needed to win another major.

"It wasn't really the performance of Augusta that's hard to get over," said McIlroy. "It's the mental aspect and the deflation of it and sort of trying to get your mind in the right place to start going forward again, I guess.

"I think I'm close.

"I still believe that I'm one of the best players in the world and I can produce good golf to have a chance of winning this week."

With Reuters