Andre Agassi is concerned an ankle injury may force him to miss next month's Australian Open and he will bypass the French Open in 2006.
The 35-year-old sprained his left ankle playing racquetball eight weeks ago.
He reinjured it while losing his first match in Shanghai on November 14 before withdrawing from the Tennis Masters Cup.
"It's actually now becoming concerning for Australia how it's been the last few weeks," the American, four times Australian Open champion, told reporters in California on Wednesday.
He said the ankle is worse now than it was two weeks ago, and that he is having trouble doing conditioning work for the season's first major tournament starting on January 16.
"Through my experience in Shanghai, I can confidently say I'll never get on the court again unless I'm 100 per cent ready," Agassi said.
Agassi said he would miss the 2006 French Open after losing in the first round of the tournament the past two years.
"Two years in a row as a result of trying to still compete on clay, I've been unable to compete at Wimbledon," Agassi told the Los Angeles Times.
"I think it's a good decision for me in the bigger picture. But I have to call my shot, take my best guess as to what I need and not playing the clay at this stage of my career beats the alternative which is putting myself through it and jeopardizing more realistic goals for me."
Agassi said he was considering playing for the U.S. Davis Cup team next year, beginning with a February tie against Romania in California.
He won the French Open in 1999 to complete his set of four grand slam titles and has played in Paris every year since 1998.