PARIS -- Serena Williams pulled out of the French Open on Thursday, a decision that was expected because the 13-time Grand Slam singles champion has been off the tour for more than 10 months.
Williams, who won the 2002 French Open, hasn't competed since early July, sidelined by two foot operations and blood clots in her lung. She returned to practice last month and said Thursday she aims to be back on tour this summer.
"While I am making good progress, unfortunately I won't be able to compete in Roland Garros as I am continuing to rehab my foot and recover from the pulmonary embolism," Williams said in a statement emailed by her agent. "I am grateful for every moment I have and the fact that I have returned to the court. I am hopeful that I will be back competing this summer. Thank you all for your continued prayers."
Her older sister Venus -- a seven-time major singles champion -- is also in doubt for the clay-court French Open, which starts May 22. Tournament organizers said Thursday they have not heard from Venus, who hasn't played since January because of a hip injury.
The French Open will be the third consecutive Grand Slam tournament missed by Serena.
Shortly after winning her fourth singles championship at Wimbledon last summer, she cut her foot on glass at a restaurant in Germany, an injury that led to two operations. The second surgery was in October, and she said she spent 10 weeks in a cast and 10 weeks in a walking boot.
The 29-year-old American was diagnosed in February with blood clots in her lung. After that, she said she needed treatment for a hematoma -- a gathering of blood under the skin -- on her stomach.
Neither Williams sister has said when she might return to the tour. Both ranked as high as No. 1 in the past, Serena is 17th this week, while Venus is 19th.
Serena was replaced in the draw for Roland Garros by Junri Namigata of Japan, the tournament said Thursday.
Two-time French Open runner-up Dinara Safina of Russia and Timea Bacsinszky of Switzerland have also withdrawn. Safina has back problems; Bacsinszky has a left ankle injury. They will be replaced by in the field by Anne Keothavong of Britain and Anna Tatishvili of Georgia.
French players Arnaud Clement -- the 2001 Australian Open runner-up -- Vincent Millot, Benoit Paire, Edouard Roger-Vasselin, Guillaume Rufin and Maxime Teixeira received wild cards for the men's draw, along with Tim Smyczek of the United States and Bernard Tomic of Australia.
Wild cards for the women's draw were given to French players Iryna Bremond, Stephanie Foretz-Gacon, Kristina Mladenovic, Pauline Parmentier and Caroline Garcia, along with Irina Falconi of the U.S. and Casey Dellacqua of Australia.