Five Australians remain on track for the season-ending Tour Championship despite failing to contend midway through the final round of the BMW Championship.

Americans Billy Horschel and Ryan Palmer share the lead in the penultimate US PGA tour event, moving to 13 under through six holes.

The duo were seemingly in a two-horse race for the trophy until Sergio Garcia eagled the seventh for the second time this week, rocketing up to third at 11 under.

Big guns Bubba Watson and Rickie Fowler share fourth, but are four shots off the pace at nine under.

World No.2 Adam Scott leads the Australian contingent at six under in 12th place having negotiated nine holes of his final round.

Scott, injured Jason Day and John Senden have secured a place to Atlanta next week for a shot at the $US10 million FedEx Cup bonus while Geoff Ogilvy and Stuart Appleby are successfully walking the tightrope so far on Sunday.

Ogilvy and Appleby sit one over for the event into their back nine, currently projected to be 24th and 26th respectively headed to the top 30 showdown next week.

The pair only need to avoid a meltdown over the final holes to secure their place, also bringing an exemption into the 2015 Masters and US and British Opens.

Marc Leishman, Matt Jones and Steven Bowditch remain at the back of the pack in Denver, ensuring their seasons end today.