Ames, who won The Players Championship by six shots for the biggest victory of his career, was supposed to speak at a charity luncheon to announce US$2.7 million in proceeds from the PGA Tour's showcase event. Finchem said Ames was home in Calgary having tests on his back.

The $6.5-million Tour Championship, which is scheduled for Nov. 2-5 in Atlanta, is reserved for the top 30 money winners.

The 42-year-old Ames is 18th on the money list with nearly $2.4 million.

Ames will also miss this week's Chrysler Championship.

Ames withdrew from the last two tournaments he played because of the injury. He pulled out of the Canadian Open in Hamilton early in September and the American Express Championship outside London three weeks later.

``It's a frustrating setback,'' he said before leaving England.

His agent at IMG in Toronto did not immediately return a phone call seeking comment. It was not clear whether Ames, who was born in Trinidad and Tobago, would be able to play the World Cup in Barbados with his brother Robert on Dec. 7-10.