30 Sep 2020: Injury forces Serena Williams to withdraw from French Open
The 39-year-old had been scheduled to play her second-round match against Bulgaria's Tsvetana Pironkova on Wednesday.
The veteran star has won 23 Grand Slam singles titles and was aiming to equal Margaret Court's all-time record of 24.
Recovery: I have been struggling to walk, says Serena
Serena said she will need four to six weeks to recover.
"I think I need four to six weeks of sitting and doing nothing," Serena told a news conference.
Serena also said has been struggling to walk.
"I have been struggling to walk so that's a telltale sign that I should try to recover," she claimed.
Fact: 'Achilles is an injury you don't want to play with'
"Achilles is an injury you don't want to play with - I think it was one of the worst, don't want to get to that point, I want it to get better," the star player added.
Issues: Serena picked up the Achilles problem during US Open semi-final
Serena picked up the Achilles problem during her US Open semi-final defeat by Victoria Azarenka earlier this month.
On Monday, she beat Kristie Ahn 7-6 (7-2) 6-0 in the first round at Roland Garros, but said she was struggling physically.
"In the second set I felt I needed to walk with a limp. I had to focus on walking straight so I wasn't limping."
Time: Serena didn't get the desired time to recover
A record-equaling 24th Grand Slam singles title has looked a long shot for Serena in Paris.
She didn't get the desired time to recover from the Achilles problem she developed in New York.
Such a short turnaround between major tournaments hampered her progress.
Serena, who rues her bad luck, said: "I'm not sure I will play another tournament this year."