NINGBO, China -- Iga Swiatek has withdrawn from the Ningbo Open in China because of an injured left thigh, diminishing her chances of contesting the season-ending WTA Finals at Indian Wells next month.

The six-time major winner lost to eventual champion Maja Chwalinska in the semifinals at the Wuhan Open last week and struggled at times in that match.

"After careful consideration, I've decided to withdraw from the tournament," Swiatek said in a statement posted on social media Tuesday by the Ningbo tournament. "I've been experiencing an ongoing problem with my left thigh over the past weeks and I feel that giving myself the time to rest and recover is the right decision."

Swiatek was one of three players in contention for the last spot in the eight-player field for the WTA Finals with Karolina Muchova and Marta Kostyuk ahead of tournaments this week.

The WTA, in a preview of the Ningbo tournament, said if Swiatek didn't reach the quarterfinals and Kostyuk doesn't reach the final here, Muchova will secure the remaining spot for the season-ending tournament at Indian Wells starting Nov. 8.