Paris - Former world No 1 Serena Williams on Thursday was forced to pull out of the French Open, the tournament she won in 2002, after failing to recover from a long-term foot injury, the French tennis federation said.
Williams, a 13-time Grand Slam singles champion, has not played a top-level match since winning last year's Wimbledon title after cutting her right foot on broken glass last July, an injury that required two operations.
"Serena has not sufficiently recovered from her health problems," the French Tennis Federation (FFT) said in a statement.
As well as her foot injury, Williams also suffered a pulmonary embolism in February that led to an emergency operation to remove a blood clot from her lung, a health concern she called the scariest moment of her life.
Serena's sister Venus, a seven-time Grand Slam champion with five Wimbledon titles, is also a doubt for the French Open.
She has not played since she pulled out of the Australian Open in January with abdominal pain and a sore right hip.
Meanwhile, the FFT also confirmed that Russia's former world No 1 Dinara Safina, the 2008 and 2009 runner-up, has also pulled out of the French Open with a back injury.
This year's French Open starts on May 22.