By Brian Keogh

Padraig Harrington has thrown in the towel on the FedEx Cup by pulling out of this week's BMW Championship in Chicago.

The Open champion, 36, missed the cut in the Deutsche Bank Championship in Boston and confessed that he is mentally shattered after playing four events in the space of five weeks.

Ranked 23rd in the FedEx Cup standings, his decision to skip the third play-off event at Cog Hill means he will almost certainly fail to remain in the top 30 that qualify for the Tour Championship in Atlanta in two weeks time.

But he explained that he badly needs to recharge his batteries if he is to have enough fuel in the tank to defend his Order of Merit crown in Europe.

Harrington confessed: "I have been out here for five weeks and I need a break. It might be the case that I won't qualify for the Tour Championship.

"But there is no point in me turning up next week and shooting four 72s. It would be better to have a break with regard to my end of season form.

"I am just tired. It is straightforward and very easy to see on the golf course.

"My short game has not been good and while it is not like I don't need the practice, it is more important for me to rest."

Harrington missed the cut by a shot in Boston after carding a pair of one over par 72s.

And he knew that he was always going to struggle after seeing his form in the opening round.

He explained: "After playing as well as I could and hitting it as well as I could in the first round, I could only shoot 72. That is a sign that you need to step away from it for a bit.

"There is nothing wrong with the game at all but sharpness. I could take a couple of days off but rather than do that I am taking the entire week off.

"I played tired golf in Boston and I made nothing happen. That is a sign that you are tired.

"That is the way the game goes sometimes. I wasn't doing much wrong, but I wasn't doing much right either.

"I know myself it is a sign of tiredness in my game. Not so much physical tiredness but mental tiredness.

"It was to be expected I suppose. As for the FedEx Cup, I am not going to start looking at the points.

"I have pulled out of the BMW Championship and whatever happens, happens. There is no point in turning up and playing the same way."