Hideki Matsuyama shot a three-under 67 to hold a one-stroke lead over Tyler Duncan after the first round of the PGA's BMW Championship at Olympia Fields, Illinois.
Mackenzie Hughes of Dundas, Ont. is third after carding a 69, one of just three golfers to break par.
Rory McIlroy is among a group that shot even-par 70, while Dustin Johnson is at 71.
Tiger Woods needs to finish around fourth to have any hope of returning to East Lake next week in Atlanta to chase the $15-million bonus for the FedEx Cup winner.
He was hovering around even par a few shots out of the lead as he finished with three straight bogeys for a 73.
With files from the Association Press