Story highlights Murray withdraws from season's first grand slam

Australian Open starts January 15

Kei Nishikori also withdraws

(CNN) Former world No.1 Andy Murray, who has not played competitively since July because of a hip injury, has withdrawn from the Australian Open.

"Sadly I won't be playing in Melbourne this year, as I am not yet ready to compete," said the three-time grand slam champion in a tweet on the Australian Open Twitter feed Thursday.

"I'll be flying home shortly to assess all the options."

Murray, now ranked 16th in the world, attempted a return at the US Open in August but pulled out two days before the start of the tournament and his only on-court appearances since have been exhibitions.

The Briton's reluctance to undergo surgery is understandable. Players who have had hip surgery in the past, such as former world No.1s Gustavo Kuerten and Lleyton Hewitt, have struggled to recapture their form.

Read More