World No. 5 Kei Nishikori has withdrawn from the upcoming Shanghai Masters due to injury and will seek to make his comeback at the Swiss Indoors later this month, his management company announced Thursday.

Nishikori retired from his second-round match at the Japan Open in Tokyo on Wednesday after suffering an injury to his left gluteal muscles, and has opted out of the Shanghai tennis tournament, which starts Sunday, due to slight stiffness in his left buttocks.

"I am so disappointed to have to pull out of the Shanghai Masters," Nishikori said in a statement. "The doctor is recommending at least 10 days rest and heavy rehab. It's disappointing for me to miss Shanghai as playing in Asia is a huge honor and pleasure for me."

Nishikori, who has his eye on playing in the ATP World Tour Finals in London for the third straight season, will return to his training base in Florida, where he will undergo rehab. The Swiss Indoors, in Basel, starts on Oct. 24.