ATLANTA — Dustin Johnson had a reasonable lie in the rough and only a few pine tree branches blocking his path to the 17th green. Neither seemed like a problem until he played the wrong shot, clipped the tree and wound up with a double bogey Saturday in the Tour Championship.

It was an example of how one hole can change everything at East Lake. And it’s why the final round of the PGA Tour season suddenly has more scenarios than Johnson cares to consider.

Johnson recovered with a birdie from the bunker on the par-5 18th for a 1-under 69, giving him a share of the lead with Kevin Chappell (68) going into the last round that will determine who wins the Tour Championship and the FedEx Cup.

For the first time since 2009, there’s a chance it might not be the same player.

“There’s a lot of scenarios that could happen,” Johnson said. “But yeah, I’m still going to go out and try to shoot as low a score as possible.”

Johnson only has to win or finish second alone to claim the $10 million bonus as the FedEx Cup champion.

Rory McIlroy, who has gone 28 holes without a bogey at East Lake, had three birdies over his last six holes for a 66 and was two shots behind. If he were to win the Tour Championship and Johnson finished in a two-way tie for second or worse, McIlroy would claim the FedEx Cup.

“It would just be great to try to win the Tour Championship, and if the chips fall my way, then so be it,” McIlroy said.

The winner of the Tour Championship has won the FedEx Cup every year since 2009, when Phil Mickelson won the tournament and Tiger Woods won the FedEx Cup.

CHAMPIONS TOUR: Scott McCarron eagled the par-5 12th and shot a 5-under 66 to take a two-stroke lead in the Pacific Links Bear Mountain Championship.

Doug Garwood was second after a 66. Colin Montgomerie was 11 under.

EUROPEAN TOUR: France’s Alexander Levy completed an 8-under 63 and the delayed second round to take a four-stroke lead in the rain-shortened European Open at Bad Griesbach, Germany.