American Billy Horschel has taken control of the US PGA Tour’s penultimate playoff event.

Adam Scott and the Australian tilt are virtually resigned to playing for FedEx Cup points rather than the BMW Championship trophy after another average day in Denver.

World No.2 Scott birdied his final three holes to shoot a one-under 69 and move to four-under for the tournament in a tie for 10th at the US PGA Tour’s penultimate playoff event, but he sits a massive nine shots shy of the lead.

American Billy Horschel fired a blistering 63 at Cherry Hills Country Club to surge to 13 under for the tournament, good enough for a three shot lead from fellow American Ryan Palmer (67) at 10 under.

US Open champion Martin Kaymer (64) and Masters champion Bubba Watson (66) share third at eight-under.

Only 30 players progress to next week’s season-ending Tour Championship in Atlanta where the overall points winner collects a whopping $US10 million ($A10.82 million) bonus.

Scott, Jason Day and John Senden are secure heading to Atlanta but know the higher seeding you have, the more chance you are of winning it all.

“It was a good bonus finish today and now I have to build on it tomorrow,” Scott said.

“I’ve got to think I am due a low round where I can put it all together and a low one will go a long way to sending me into next week in a stronger position, which is important.”

Scott is currently projected to be 14th heading to Atlanta but should he finish in the top five in Denver he could make a significant jump up the standings.

Day, who withdrew during round two with a back injury, is currently projected to be 12th while Senden, who sits one-under par and tied 23rd, is set to be 18th.

Sunday’s final round will be a huge one for Geoff Ogilvy (+1, tied 34th) and Stuart Appleby (+2, tied 39th) as they try to protect a place to next week.

Currently Ogilvy is projected 24th and Appleby 29th but both have hovered in and out of the top 30 throughout the event.

If they hold on they will not only survive but also pick up exemptions into the Masters and US and British Opens next year.

“I don’t have a lot of experience being in the middle of a field and it meaning something but I am not too worried,” Appleby said.

“I would like to get an under par round tomorrow and cement my place. If I can just strike the ball a little better and get some putts to drop I should be fine.”

Marc Leishman (+2), Matt Jones (+6) and Steven Bowditch (+9) will be eliminated after the final round.