The top 30 players in the standings get into the field at East Lake, but they have to get through Conway Farms, just outside of Chicago, first.
Based on their Day 1 efforts, Lee Westwood, Dustin Johnson and Billy Horschel are all in danger of playing their way out of the top 30.
Westwood, who came into the week at No. 30, had a terrible first round, shooting 9-over 80, though he did so with some kind of injury nagging him.
Johnson is 1 over par on the day, now sitting at 30th in the standings, down from 23rd before balls were in the air on Thursday. Horschel, who was 1 spot ahead of Johnson at 22nd, is now 29th.
Last year, two players were bounced from the top 30 in the penultimate stage of the playoffs, with Kyle Stanley and defending FedEx Cup champion Bill Haas going from in the Tour Championship to 31st and 32nd, respectively.