Keegan Bradley, the last man into the BMW Championship field, shot a 6-under-par 66 to take the first-round lead before a dangerous weather delay interrupted the end of the action on Thursday in Castle Rock, Colo.
The weather delay kicked in at 3:33pm local time with just eight players left on the course at Castle Pines Golf Club, including Japan's Hideki Matsuyama, alone in second at 5 under par with one hole to finish. Matsuyama won last week's playoff opener, the FedEx St. Jude Championship.
Bradley didn't fare as well at the St. Jude but squeaked into this week's field at No 50 on the points list. The upcoming US Ryder Cup captain posted a bogey-free round with six birdies, including a 10-footer to finish up at No 18.
Because playoff events are worth four times the points of a regular-season tournament, Bradley would rocket into the top five in points with a win in the thin air of Colorado.
Tied for third at 4-under 68 were Sungjae Im of South Korea, Alex Noren of Sweden, Adam Scott of Australia and Corey Conners of Canada.
Northern Ireland's Rory McIlroy made a 21-foot eagle from off the green at the par-5 14th to get to 3 under. He was facing a 20-foot birdie putt at the 18th when the weather delay began. The three-time FedEx Cup champion was tied at 3 under with Xander Schauffele, South Korea's Si Woo Kim and Nick Dunlap, the latter of whom had three holes left.
World No 1 and FedEx Cup leader Scottie Scheffler turned in a 1-under 71 and was seen grabbing at his lower back during his penultimate hole. Scheffler later said he woke up sore on Thursday morning and was "laboring" but is not injured.
Reigning BMW Championship and FedEx Cup winner Viktor Hovland of Norway also opened with a 71.