Tiger and Phil are 'just getting older' - McIlroy

World No 1 Rory McIlroy is not convinced the absence of Tiger Woods and Phil Mickelson from the US PGA Tour Championship signals a changing of the guard in golf.

But the 25-year-old reigning PGA Championship and British Open champion noted on Wednesday, the eve of the season-ending event, the passing years for Mickelson, 44, and Woods, who turns 39 in December.

"They are just getting older," McIlroy said. "Phil is 43 or whatever and Tiger is nearly 40. So they are just getting into sort of the last few holes of their careers and that's what happens. It obviously just gets harder as you get older.