Serena Williams has withdrawn from the season ending WTA Championships due to injury.

Williams, who recently lost her world No.1 ranking to German Angelique Kerber, posted a short video on social media explaining her decision to her fans.

“It's been a really tough year for me, dealing with these shoulder injuries,” Serena said.

“My doctor insists that I stay home and heal it.

“I only have wonderful memories of playing in Singapore and I will really miss my fans.

“I want to wish everyone a great time and I hope it will be an amazing tournament – it always is.”