From the release:
During this evening's golf course greens maintenance at the Atlanta Athletic Club, there was minor damage caused to the edges of both the 14th and 17th greens. This damage is believed to be the result of a significant rise in the dew point at approximately 7:00 p.m., which caused the brushes on the mowers on those greens to stick in the grass and damage the turf.
The damage has already been fully repaired by the grounds staff at the Atlanta Athletic Club, led by Ken Mangum, the Director of Golf Courses and Grounds.
This will not affect the opening round of the 93rd PGA Championship and we look forward to play in the first round tomorrow in the season's final major, beginning at 7:30 a.m. ET