NEW YORK -- Monica Seles pulled out of the U.S. Open on Friday with a left foot injury that has sidelined her since May and could end her career.

The nine-time major champion, including the 1991-92 U.S. Opens, hasn't played a competitive match since losing in the first round of the French Open.

"Monica has been advised by her doctors that the stress fracture in her left foot is not yet healed 100 percent," her agent, Tony Godsick, said in a telephone interview. "She is very disappointed, as she loves the U.S. Open and the New York crowds."

He said it's not clear whether Seles will play again this season. Seles was not available for comment.

After she was beaten by eventual semifinalist Nadia Petrova at the French Open, Seles said she needed to take some time away from the game to see if her injured feet will heal enough to allow her to play without pain.

"I know I'm in the later stages of my career," she said at the time. "I don't have the luxury of taking five-to-six months off. At the same time, I don't want to have surgery."

Since then, she pulled out of several tournaments, including Wimbledon and a hard-court event this week in Toronto.