The 37-year-old is confident of playing at the 2019 French Open, despite being forced to pull out of the Italian Open in Rome due to a knee injury.
Williams' latest injury setback follows on the back of two previous withdrawals this year. The American pulled out of the Masters Miami Open due to the same injury, while she also exited the BNP Paribas Open at Indian Wells prematurely with a viral illness.
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Despite her latest withdrawal, the 23-time Grand Slam champion is confident of recovering in time for Roland Garros.
"I'll be concentrating on rehab and look forward to seeing you all at the French Open and next year in Rome," Serena said in a statement.
"I haven't been able to train or practice a lot, I was out much longer than I expected.
"I feel like I'm taking it one day at a time."
Williams last Grand Slam singles title came back at the Australian Open in 2017.