SYDNEY -- Hunter Mahan withdrew Friday morning from the Australian Open because of soreness behind his right shoulder, raising questions about whether he can play next week in the Presidents Cup.
Mahan said he fully expects to be play at Royal Melbourne, and believes he will be ready to go after a few days of rest.
The pain is nothing new, although he said typically it has been behind the left shoulder. He started feeling pain Wednesday night, and it gradually improved during his opening round at The Lakes when he shot 73 while playing with John Daly and Craig Parry.
"It wasn't great for nine holes, then they came out and popped my back and it was a little better," Mahan said. "It's just the rotation. It's fired up to the point that I can't get through the ball."
Mahan said he has kept U.S. captain Fred Couples apprised -- Couples also is playing the Australian Open. And while Mahan expects to be ready for the Presidents Cup, he left some doubt by saying, "If Fred has to call, then ... ."
That was reference to PGA champion Keegan Bradley, who Couples has said would be the replacement if any of his players were injured.
Mahan leaves the U.S. team with two players whose health is in question. Steve Stricker has not played since Sept. 25 at the Tour Championship because of a neck injury that has weakened his left arm.
Stricker chose not to play at Disney as his tune-up for the Presidents Cup, instead going to Arizona this week to practice. He has said he expects to play, and likely will be the partner again for Tiger Woods. They went 4-0 as a team last year.
Bradley just returned home to Florida after two weeks in Shanghai.
Mahan tried to play Friday morning. He said the pain tends to go away once he warms up, but that wasn't the case. Physical therapists worked on his shoulder, and his shirt was untucked on the range as he debated playing. Ultimately, he decided it was better to rest.
"It came on Wednesday night, and Thursday it wasn't great," Mahan said. "Today was the worst it has been. The more I keep swinging, the worse it gets. But I don't see this being a long-term problem for next week."