World No 6 Collin Morikawa, a two-time major winner, withdrew from the PGA Truist Championship on Monday, taking a rest before next week's PGA Championship at Aronimink.
The 29-year-old American, who captured the 2020 PGA Championship and 2021 British Open, has battled several injuries in recent weeks, including a back injury that forced him to pull out of The Players Championship in March after one hole.
Morikawa, who won his seventh career PGA Tour title in February at Pebble Beach to snap a 28-month win drought, shared 62nd last week at Doral.
He also withdrew from last month's PGA Texas Open ahead of the Masters, where he shared seventh. He shared fourth the following week at the Heritage tournament.
World No 2 Rory McIlroy, coming off his second consecutive Masters victory last month at Augusta National, leads this week's field at Quail Hollow, where McIlroy has won four times.
The tuneup for the year's second major tournament also features England's third-ranked Matt Fitzpatrick, fourth-ranked American Cameron Young who won last week at Doral and England's fifth-ranked Justin Rose and seventh-ranked Tommy Fleetwood.