Jim Furyk will have to wait one more day to try to end three years without a victory on the US PGA Tour after a heavy rainstorm on Sunday postponed completion of the final round of the $US8 million ($A8.69 million) BMW Championship, the penultimate event of the playoffs.

Rain-soaked fairways and greens made delays the order of the day with only six of the 70-man field completing their final rounds and the top 22, including Furyk, failing to even get a shot away.

Furyk will now bring his one-shot lead to a Monday finish before the battle for the season-long FedEx Cup heads to the Tour Championship in Atlanta.

Furyk sits one clear at 13-under par from fellow American veteran Steve Stricker, who is at 12-under and outright second.

Reigning FedEx Cup champion Brandt Snedeker is third at 11-under, Zach Johnson fourth at 10-under and world No.1 Tiger Woods fifth alone at nine-under.

Jason Day and Matt Jones were also amongst those who didn’t get to start, leading the Australian charge in a tie for 11th at six-under.

Day, sick with a severe sinus cold, was actually thankful for the rest, although he couldn’t spend it in bed as he was on a constant holding pattern at the course.

The Queenslander is already safe for Atlanta, as is Masters champion Adam Scott, who played the opening 10 holes in three-under to move to one-under and a tie for 33rd.

Scott is projected to drop from third on the season-long points list to fifth, still high enough to ensure a win at the Tour Championship would also bring the FedEx Cup title and the $US10 million ($A10.86 million) bonus that comes with it.

Jones can still make a late play for Atlanta if he can push into the top five of this event.

Marc Leishman’s season will end in Chicago after he dropped to four-over for the tournament with just 11 holes left to negotiate.