Chris O'Meara/Associated Press
Birdies have flown into the cups at TPC Harding Park during the first two hours of the PGA Championship.
Before the high-profile groups hit the course, Scottie Scheffler set the pace for the competition with three birdies in his first four holes.
Tony Finau, Jason Day, Daniel Berger and Xander Schauffele were among the golfers to open their respective rounds in red numbers.
Brooks Koepka, Tiger Woods and Justin Thomas are among the previous major championship winners out on course for the morning session.
PGA Championship Leaderboard
Scottie Scheffler (-2)
Brian Harman (-1)
Jason Day (-1)
Xander Schauffele (-1)
Daniel Berger (-1)
Collin Morikawa (-1)
Eight other golfers (-1)
Scores as of 11:45 a.