Williams ruled out with Achilles injury as Tsvetana Pironkova progresses to the third round at Roland Garros by walkover.
Serena Williams is out of the French Open.
The 23-time Grand Slam singles winner was due to meet Tsvetana Pironkova in the second round at Roland Garros on Wednesday (30 September).
But the Bulgarian has been given a walkover with Williams suffering from an Achilles tendon problem she picked up at the US Open.
The American, who turned 39 on Saturday, had complained of the injury after her first-round win over Kristie Ahn.
Speaking to the press after her withdrawal, Williams said she would need between four and six weeks to recover and that she does not expect to play again in 2020.
"I felt like I needed to walk with a limp. I had to focus on walking straight." - Serena Williams
The last of her 23 Slam singles titles came at the 2017 Australian Open before she took time out to give birth to daughter Olympia.
After her return to the tour in March 2018, she made the finals at Wimbledon and the US Open in both 2018 and 2019 but was beaten on each occasion.
At the US Open earlier this month, she went out in the semi-finals to Victoria Azarenka having "overstretched" her Achilles in the deciding set.
She remains one behind Margaret Court's record 24 Slams, although 13 of the Australian's titles came before the start of the Open era.
Williams decided to take her chance at Roland Garros, but now knows she needs "four to six weeks of sitting, doing nothing" to allow it to heal.
She added, "Doing the math on that, more than likely – I don’t know if I’ll be able play another tournament this year. It will mean a lot of time to fully recover for the future.
"I feel like my body is willing. This is not a nagging injury. This is an acute injury. If it was my knee, that would be more devastating for me, but this is something that just happened, and it’s super acute.
"I think my body is doing really, really well. I just ran into, for lack of a better word, bad timing and bad luck, really, in New York.
"I love playing tennis. I love competing and I love being out here. It’s my job and I’m pretty good at it still. So, until I feel like I’m not good at it, I’ll be OK. And I’m so close to some things. Like, I’m almost there. That’s what keeps me going." - Serena Williams