Wuhan, China: World No. 1 Serena Williams announced on Thursday her withdrawal from next week’s China Open in Beijing and the WTA Finals in Singapore, ending her season.

“I am taking a proactive step and withdrawing from tournaments in Beijing and Singapore to properly address my health and take the time to heal,” the 21-time Grand Slam winner said in a statement.

The China Open first tweeted the announcement, but the WTA has not confirmed Serena’s withdrawal.

Serena has not played since she lost in the semi-finals of the US Open to Italy’s Roberta Vinci, one of the most shocking upsets in tennis history.

“It’s no secret I’ve played injured most of the year — whether it was my elbow, my knee, or, in the final moments after a certain match in Flushing, my heart,” Serena said.

Serena’s coach Patrick Mouratoglou told ESPN earlier this week that she was intensely disappointed after missing out on a fifth consecutive Grand Slam crown and hinted that she may withdraw from the remaining tournaments of the season.