He figures there are between 20 and 30 players who have a legitimate chance of winning at Oak Hill.
"It makes for exciting golf and it makes for unpredictable golf," Mahan said. "You just never know who is going to come out on top."
Already this year, there have been a couple of first-time major winners — Rose and Masters champ Adam Scott, who were scheduled to play in the afternoon with British Open winner Phil Mickelson.
That said, Woods is an overwhelming favorite to capture his 15th major title, even with the long gap since No. 14. He's coming off a seven-stroke victory in the Bridgestone, and by no means does anyone seem to think he's done winning on the biggest stages.
"Having him back, having him play well, having him win like he's won this year, is great for the game of golf," said Mickelson, who is back up to No. 2 in the world rankings. "He's not hitting the (poor) shots he did for a few years. He's playing solid, and he played great last week."
Of course, historic Oak Hill might not be the best course for a major neophyte to break through. The narrow fairways and tricky greens certainly seem set up for a more established winner.
"These traditional-style courses really test patience and strategy," Scott said. "An experienced and mature golfer should have a slight advantage in that."
Tom Watson, who has won every major title except the PGA, was asked who might have the best chance at being a first-time winner this season. He couldn't come up with a name.
"Who can put the ball in the fairway the most?" he asked. "This may be the toughest golf course, but the fairest golf course that we play. Pick 'em. Somebody's going to win this thing, and that person is going to play awfully well."