World number one Jason Day headlines the marquee trio at this week's The Barclays tournament which kicks off the first round of the PGA Tour playoffs.

Defending champion Day is joined by Dustin Johnson and Adam Scott at the event which will cut the FedEx Cup playoff field to 100 and give others a chance to bid for spots in the Ryder Cup.

Also in the field of 121 is Justin Rose who is fresh off winning the gold medal in the Rio Olympics. Rose will tee it up on Thursday at Bethpage Black in Farmingdale, New York in a group with Zach Johnson and Kyle Reifers.

Australia's Day, Johnson, of the US, and Scott have combined for seven wins this season and are the top three players in the playoff standings.

All three are coming off a break, having not played since last month's PGA Championship in New Jersey.

Scott is trying to get back to the form that saw him win two straight tournaments earlier this season in Florida. He has just one top-10 finish since those victories.

In 2012, Johnson tied for third at this event, the last time it was held at Bethpage, located 62 kilometres (39 miles) east of New York.

England's Rose is entering the playoffs at number 51 in the FedEx Cup standings.

So the first Olympic golf champion since 1904 has some work to do in the next three weeks because he must get into the top 30 to qualify for the Tour Championship.

"I really enjoyed my Olympic experience," Rose said. "I was obviously one of the golfers excited about the prospect of going down there to Rio, and just embracing representing your country and embracing being an Olympian.

"And obviously now to come away with a gold medal and be called Olympic champion is quite clearly just a huge carrot."

Phil Mickelson will be seeking his first win of 2016 on a course where he has had a couple of noteworthy second-place finishes. He was runner-up at both the 2002 and 2009 US Opens.

American Patrick Reed enters this week on the bubble for the Ryder Cup. Reed is clinging to the eighth and final automatic qualifying spot.