Early Thursday morning, according to Sports Illustrated
, the China Open’s official account posted a message via the Chinese Twitter service Weibo saying: "This is regrettable news and we hope Serena Williams will get well soon."
Williams, later in the afternoon, tweeted
a message of her own ''Flu no fun,'' but made no mention of the China Open.
The China Open is a Premier-level event on the WTA schedule and is one of four "mandatory" tournaments for 2012. The 15-time Grand Slam champion won
the China Open in 2004.
Her absence is a big blow to the organizers of the Beijing event as the world number four -- who has already qualified for the season-ending WTA Championships in Istanbul, Turkey, next month -- is one of the tour's most bankable stars, Channel NewsAsia
The WTA China Open starts on Saturday with Agnieszka Radwanska of Poland defending her title after against a host of top players, including world number one Victoria Azarenka, Russian Maria Sharapova and home favorite Li Na. Williams will be replaced by Switzerland's Romina Oprandi.
The currently fourth-ranked Serena just enjoyed one of the best summers in the history of women's tennis. The 31-year-old is now just the second woman ever to complete the Career Golden Grand Slam, winning all four Grand Slams and Olympic Gold.
"It's too much. I never expected gold in singles. I was so happy with my doubles golds. I thought if my career's over I have my gold medal, now I have everything, literally. I have everything there is to win in tennis," an overjoyed Williams said in her on-court interview moments after crushing Maria Sharapova at the 2012 London Olympics, according to WTA
News. "Where do I go from here?"
"Now I can go to Disneyworld," she added.