Serena Williams of the US reacts losing a point against Karolina Pliskova of Czech Republic during their 2016 US Open Womens Singles semifinal match at the USTA Billie Jean King National Tennis Center in New York on September 8, 2016. TIMOTHY A. CLARY/AFP/Getty Images

Serena Williams has withdrawn from the season ending WTA Championships due to injury.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