Phil Mickelson has turned down the chance to take on Padraig Harrington in October's PGA Grand Slam of Golf in Bermuda.

With US Open winner Tiger Woods out with injury and Harrington winning two majors this season, two alternates were needed to make up the most exclusive fourball in golf.

Left-hander Mickelson and two-time US Open winner Retief Goosen topped this year's Major Champions Point List and earned the right to join Harrington and Masters champion Trevor Immelman at the Mid Ocean Club in Bermuda from October 14-15.

But Mickelson declined the invitation and has now been replaced by fellow American Jim Furyk, who will play in the PGA Grand Slam of Golf for the third straight year despite the fact that it has been five years since he won his only major in the 2003 US Open.

This is the second time in three years that two alternates were required to fill out the field.

Mickelson declined to go in 2006 after winning the Masters and Woods won two majors that year.

Alternates, who must be major champions, are determined by a points list from how they fared in the majors.

The PGA Grand Slam of Golf boast a massive $1.35m (€900,000) purse with the winner banking $600,000 (€400,000), second place $300,000 (€200,000), third place $250,000 (€170,000); and fourth place $200,000 (€130,000).