Serena Williams has pulled out of the US Open to recover from a torn hamstring

• Serena Williams is pulling out of the 2021 US open to recover from a hamstring injury.
• Williams had to pull out of Wimbledon due to a hamstring injury in June.
• Grade 2 and 3 hamstring injuries can typically take several weeks or even months to recover.

Serena Williams announced she is pulling out of the 2021 US Open on Wednesday to recover from a torn hamstring.

The 39-year-old American tennis star announced her withdrawal via an Instagram post, saying it was a difficult decision that she came to after consultation with her doctors.

"After careful consideration and following the advice of my doctors and medical team, I have decided to withdraw from the US Open to allow my body to heal completely from a torn hamstring," Williams wrote.

"New York is one of the most exciting cities in the world and one of my favorite places to play - I'll miss seeing the fans but will be cheering everyone on from afar. Thank you for your continued support and love. I'll see you soon."

Williams suffered a hamstring injury in her right leg during her first-round match at Wimbledon in June, and limped off the court in tears. She has only missed the US Open three times in her career since she began to compete at major events in 1998.

Williams had a chance to break the all-time record for most Grand Slam titles. She currently has 23, which is just one less than former Australian tennis star Margeret court who won 24 from 1960-1973.

But Williams is running out of time to break that record, as her last Grand Slam title came at the 2017 Australian Open.

Now, at an older age for professional tennis players, she will have to make a comeback from an injury that can take weeks or even months to fully recover.

Williams did not specify the severity of her injury in her announcement or whether it was the same leg. But if the injury is causing her to miss a major tournament, it is likely either a grade 2 or grade 3 hamstring tear.

If it is a grade 2 hamstring injury then it means she suffered a partial muscle tear and it hasn't fully ripped, according to Healthline. Recovery would take 4-8 weeks of rest, in which time she would need to wear an elastic compression bandage and to treat the injured area with ice. She would also need to keep her leg constantly elevated to decrease swelling.

If it is a grade 3 hamstring injury then it means her hamstring muscle ripped completely or tore off the bone, according to Healthline. Recovery for that severe of an injury would take up to three months of treatments and could require surgery if it doesn't heal naturally, which could extend the recovery time to 5-6 months.

Williams has said she won't retire until she wins one more Grand Slam to tie Court with 24 for the most of all time. But for her to come back to try and get the job done next year at the age of 40 will be a daunting challenge, especially having suffered two hamstring injuries in the same year.

But to Williams' credit, she was able to return to tennis to win her last grand slam after child birth in 2017, so she's conditioned to come back from strenuous circumstances to claim victory.