It's a tough old life.

Careering about trying to fill your wheelbarrow with bills from a $67m prize pot takes it out of you, after all.

The PGA Tour's money-soaked FedEx Cup reaches its conclusion this week in Atlanta with just 30 players having a rummage among the riches of this chest of golfing goodies, hoping to be the one who carts off a bonus prize of some $10m.

It's nice work if you can get it. There are some, of course, who are quite happy not to be there.

"My primary goal is to rest and prepare for the Ryder Cup," said a jiggered Phil Mickelson, having withdrawn from the BMW Championship after two rounds last Friday once he realised he had no chance of qualifying for this week's lucrative last hurrah in the Tour Championship.

Ducking away prematurely from a tournament was something of a public relations blunder from the likeable lefty but it was clear that the hectic schedule had taken a heavy toll in this exacting test of skill, stamina and mental resolve. With the Ryder Cup just a fortnight away, Mickelson didn't want to be wheezing and spluttering into Gleneagles with nothing in his tank.

Since the start of the US Open in June, there have been three majors, a world golf championship event and four FedEx Cup play-offs to keep the top brass in the world order on their toes. It is a hectic spell, and the balancing act between maintaining sharpness and staving off the effects of fatigue becomes more problematic at this time of a long campaign.

"A lot of people forget that it's very, very difficult for someone who is staying in hotel rooms every single week," were the recent words of Martin Kaymer. "I've been in rooms now for five weeks in a row. You can't really skip an event."

Sergio Garcia, who dunted a greenside chip into the pond at the weekend as his hopes of victory gurgled away in a watery grave, also expressed a sense of running on empty. "It's what happens when you're not mentally sharp," said the Spaniard.

Garcia and Kaymer are one of only four European Ryder Cup players competing in Atlanta. Team USA has 10 representatives on show.

The leading two on the current FedEx standings, however, won't be heading for Perthshire. Chris Kirk, who heads the points list following his recent win in the Deutsche Bank Championship, was overlooked for a wild card by US skipper Tom Watson while Billy Horschel's success in last Sunday's BMW Championship came a week after the captain's picks had been named. Watson has always insisted that he wanted "hot hands" on his team but having to announce his wild cards with two events of the FedEx series still to play doesn't really make any sense.

Should either Horschel or Kirk win again this weekend, it may be Watson, not some of the jaded superstars, who will need a lie down.