Los Angeles: US superstar Serena Williams has withdrawn from the elite WTA Finals in Singapore, saying she's still working to recover from the shoulder troubles that hindered her in 2016.
The Women's Tennis Association (WTA) announced Williams' withdrawal from the event that starts on 23 October on their Twitter feed, posting a video of Williams herself explaining the decision.
— WTA (@WTA) October 17, 2016
The 22-time Grand Slam champion pulled out of two tournaments in China after being knocked out of the semi-finals of the US Open.
That defeat saw Williams' 186-week reign atop the world rankings end as Germany's Angelique Kerber reached the summit and captured the Flushing Meadows title into the bargain.
Williams claimed just one Grand Slam title in 2016, at Wimbledon. After that, shoulder troubles hampered her in Rio where her hopes of a fifth Olympic gold medal were crushed in the third round.
WTA CEO Steve Simon said in a statement that organisers were "as disappointed as the fans".
"We wish her a speedy recovery and look forward to seeing her back competing, fit and healthy," he added.
Williams' withdrawal opens up the eighth qualification spot to Britain's Johanna Konta, Spain's Carla Suárez Navarro and Russia's Svetlana Kuznetsova.
Either Navarro or Kuznetsova must win the title in Moscow at the VTB Kremlin Cup next week in order to edge out Konta for the eighth and final qualifying spot.
The tournament in Singapore will see reigning champion Agnieszka Radwanska defending her title against current top seed Kerber.