"Not booked for such a round," said Terry Prone, a McIlroy PR agent. "Still going through the ankle rehab process."
The world No. 1 -- who could lose that top ranking this week to Jordan Spieth at the WGC-Bridgestone Invitational -- McIlroy missed his first of two major title defenses in 2015, skipping the Open Championship last month at St. Andrews after he suffered a ruptured ATFL ligament in his left ankle during a July 4 soccer game with friends. The Ulsterman has maintained that he would take a long-term view of his recovery and not play until he's fully ready.
The four-time major winner is also skipping his title defense at Firestone C.C. this week in favor of more rest for his ankle.
McIlroy won last year's PGA Championship at Valhalla by a shot over Phil Mickelson. When the PGA was last contested at Whistling Straits in 2010, McIlroy finished tied for third with Zach Johnson.