Her last tennis match? Back in January, at the Australian Open at Melbourne Park, when the defending champion, clearly overweight and shockingly inept with her stroke-play, was beaten in the third round.
The American, a two-time Wimbledon champion and a winner of seven grand slams overall, dropped out of the world top 100 this week, her lowest ranking for about a decade. There are now genuine doubts if the world No.106 will play again.
Williams, 24, has multiple interests outside tennis. She has been working on her acting career (one of her recent roles came in the medical drama ER in which she played a mother whose child was trapped inside a burning building), and she also has her own fashion label - Aneres, as in Serena spelt backwards. Other recent projects have included working with Estee Lauder on its cosmetic range and starring in a reality television series with her sister Venus. She has also demonstrated a Paris Hilton-style liking for premieres and parties.
With all that going on, what appeal can the practice court and the gym possibly hold for the aspiring actress and fashionista?
Williams once dominated the sport with her athleticism around the court and the ferocity of her shots, but she has been struggling with fitness and injuries for some months now.
So concerned has the tennis world been with Williams's attitude towards the sport that two of the greats, Chris Evert and Martina Navratilova, have been moved to publicly question her. Evert and Navratilova believe that Williams has been wasting her undoubted talent and spending too much time on her off-court interests. How many more grand slam titles could Williams win if she applied herself properly?
Evert has written an open letter to Williams in the May issue of Tennis Magazine, advising her to have a rethink about her tennis career. "In the short term you may be happy with the various things going on in your life, but I wonder whether 20 years from now you might reflect on your career and regret not putting 100 per cent of yourself into tennis. Because, whether you want to admit it or not, these distractions are tarnishing your legacy," Evert wrote.
"I don't see how acting and designing clothes can compare with the pride of being the best tennis player in the world. Your other accomplishments just can't measure up to what you can do with a racquet in your hand. Just remember you have an opportunity of the rarest kind - to be the greatest ever."
Serena Williams
Serena Williams
Serena Williams
Serena Williams
Serena Williams
Serena Williams
Serena Williams
Serena Williams
Serena Williams
Serena Williams
