Williams will lose her number one ranking on Monday
Serena Williams is unlikely to play again this year following a setback in her recovery from a foot injury.
The American has not played since winning Wimbledon in July after cutting her foot, but she had hoped to play in this week's WTA tournament in Linz.
After re-straining her foot in training, though, she told her official website: "I tried too hard and did too much too soon.
"I am likely out for the year. I feel completely heartbroken and devastated."
Tournament organisers confirmed Williams' withdrawal from the tournament in Linz on Sunday.
A comeback at the modest Linz tournament would have allowed Williams to get herself in condition for the season-ending WTA Championships in Doha at the end of October.
But she will now knuckle down with a view to returning fit and firing next season, adding: "After practising on Sunday morning I felt discomfort in my foot and tests by my doctor revealed that I had unfortunately re-strained it, as a result of over training.
"I was really looking forward to beginning my comeback in Linz, followed by the year-end championships in Doha, but [now] I plan on coming back stronger and better."
Williams, 29, will lose her world number one ranking when the latest WTA rankings are published on Monday, after 20-year-old Dane Caroline Wozniacki secured top spot by reaching the quarter-finals at the Beijing tournament.
Former world number one Ana Ivanovic accepted a late wild card into the WTA tournament in Linz at the weekend.