World number eight Madison Keys will miss next month's Australian Open after undergoing wrist surgery, the American said on Friday.
Keys, 21, who made the round of 16 at all four grand slam tournaments last year, had the procedure in early November and would not be ready for the season-opening grand slam that begins at Melbourne Park on Jan. 16.
"Three days after the year-end WTA Championships I had minor arthroscopic surgery on my left wrist," she said on Twitter.
"The procedure was very short, did not involve any tendon issues and went very well ... I don't want to rush back and need to take my time to be fully ready to perform my best on the court."
Keys, who plays right-handed, also revealed she was being coached again by former world number one Lindsay Davenport, having worked with Thomas Hogstedt for the last year.
"I am very excited about working with Lindsay again," Keys added. "She's helped me reach great results in the past and we make an excellent team!"
(Reporting by Andrew Both in Cary, North Carolina; Editing by Greg Stutchbury)