Serena Williams withdrew from Roland Garros on Wednesday as the American's bid for a 24th Grand Slam title suffered another blow, sparking further doubts over the 39-year-old's long-term future in the sport.

Williams, a three-time champion in Paris, had arrived at the tournament carrying an Achilles tendon injury which she suffered in a gruelling US Open semi-final defeat to Victoria Azarenka.

"The Achilles didn't have enough time to heal after the US Open," said Williams who had been due to face Bulgaria's Tsvetana Pironkova in the second round at Roland Garros later Wednesday.

"I was struggling to walk and that is a tell-tale sign that I should try to recover."

The injury likely means she will miss the rest of 2020 leaving the Australian Open in 2021 as her next chance to equal Margaret Court's all-time majors record.

"I need four to six weeks of sitting and doing nothing," said Williams, the Roland Garros champion in 2002, 2013 and 2015.

"It's more than likely that I won't play another tournament this year."

Williams, now into her fourth decade on tour, has not won a Slam since capturing a seventh Australian Open in 2017 when she was pregnant.

Since then, it's been a series of near-misses for a player who also pulled out of Paris in 2018 on the eve of an eagerly-awaited last-16 clash with Maria Sharapova.

After returning from giving birth, she reached the finals of Wimbledon and the US Open in 2018 and 2019.

In 2020, she fell in three sets in the fourth round in Australia to China's Wang Qiang while the cancellation of Wimbledon was another roadblock.

She will leave Paris knowing full well that such a disrupted season represented her best opportunity to add to her majors haul.

In New York, six of the world's top players opted not to play.

At Roland Garros, four of the leading 10 are missing - world No 1 and defending champion Ashleigh Barty, US Open winner Naomi Osaka, 2019 US Open champion Bianca Andreescu as well as Swiss number 10 Belinda Bencic.

Past health scares

However, it would take a lot to convince Williams to call time on her groundbreaking career having overcome more serious hurdles than an Achilles injury in her time.

In 2011, a pulmonary embolism caused a clot in her lung.

"I was on my death bed at one point - quite literally. I've had a serious illness but at first I didn't appreciate that," she said at the time.

Seven years later, she revealed that she had another close encounter with her own mortality when giving birth.

"I almost died after giving birth to my daughter, Olympia," she said after undergoing an emergency caesarean section.

On Wednesday, Williams gave no indication that she was on the brink of retirement from a career which has brought her 73 career titles, $93.5 million in prize money and a 23-Slam haul which started in 1999 with the first of her six US Open crowns.

"I always give 100 percent, everyone knows that. Maybe even more than 100 if that's possible. I take solace in that," she told reporters.

"I think the Achilles is a real injury that you don't want to play with because that is not good if it gets worse."