Webb Simpson didn't slam the door on the possibility of someone else winning the FedExCup after Thursday's first round, but he did leave it open a crack.

Simpson, the top-ranked player and favorite to win the $10 million bonus that comes with winning the playoffs, shot 1 under on Thursday in the first round of the Tour Championship at East Lake.

Simpson, who bogeyed No. 18, trails leader Keegan Bradley by five strokes.

While a Simpson victory in the Tour Championship will secure the playoffs, it's not necessary. There are myriad victory-less scenarios that guarantee he will be crowned the champion.

But he does have small reason for concern: With a lot of golf left over the next three days, Simpson trails two of the remaining four men who, like himself, can win the FedExCup by winning the Tour Championship, without any other situational conditions. Luke Donald, ranked fourth in the world, shot 4 under and No. 5 Matt Kuchar shot 3 under.

As for the other two, No. 3 Justin Rose finished 1 under and No. 2 Dustin Johnson, Simpson's playing partner, shot an even-par 70.

"There's a lot of things that go along with winning this week for me and a few of the other guys," Donald said. "I'm sure there's a little bit of added pressure. That's why I was kind of proud of the way I played today."

After birdieing two of his first three holes, Simpson bogeyed two of the next three, including the difficult par-3 No. 6.

However, he bounced back with birdies on Nos. 7 and 8 to get back to 2 under. After a series of pars he bogeyed No. 14 to fall back to 1 under.

Simpson, who led the Tour this year in scoring on the par 5s (134 under), took advantage of his length on No. 15. After a perfect drive, he dumped his second shot into the bunker to the right of the green. He blasted out to within inches of the pin and made the birdie putt to get back to 2 under.

After a wayward drive right on 16, Simpson hit his approach into another bunker. He eventually made par.

The wet conditions that suspended play while Simpson was on No. 16 seemed to affect his tee shot on No. 17. He had a helicopter-like flailing of his arms at the finish of his swing and the drive went way right near some hospitality tents. He saved par by hitting onto the green with an amazing hybrid shot out of the rough.