Britain's Andy Murray says he may have to consider surgery after withdrawing from the Brisbane International because of his long-term hip injury.
The 30-year-old is down to 16th in the world, having not played since July.
Murray said on Instagram surgery was a "secondary option, something I may have to consider but let's hope not".
The Australian Open starts in Melbourne on 15 January and Murray added he would decide by the weekend whether to stay in Australia or fly home.
Murray had been given a bye to the last 16 in Brisbane and was due to play American Ryan Harrison on Thursday.
The former world number one said: "It's quite demoralising that when you get on the court it's not at the level you need it to be to compete at this level. It's really hurting inside."
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In an earlier statement announcing he would not be playing in Brisbane, three-time Grand Slam champion Murray, who won the event in 2012 and 2013 said: "I'm very disappointed to be withdrawing.
"I came here with every intention of making a strong start to the year."
Murray has not played competitively since his defence of the Wimbledon singles title ended in a five-set defeat by Sam Querrey in July, when he was hampered by the hip injury.
He made an unsuccessful attempt to return at the US Open in August, pulling out two days before the start of the tournament.
In a recent interview, Murray said he would be content to be playing at "30 in the world level" given his lengthy injury problems.
"I just want to enjoy playing again. I've really missed it the last six months or so," he said.
Russell Fuller, BBC tennis correspondent
This heartfelt and poignant post from Murray is the first time he has publicly voiced the anxiety that many others have felt for him and for his future in the game.
He will have approached this period of rehabilitation as meticulously, thoroughly and professionally as everything else in his career. And now - as he approaches six months away from the match court - he has discovered all too painfully that it has so far not been sufficient.
Murray is still very reluctant to opt for surgery, but he may come to the conclusion over the next few days that he has little alternative.
Murray has never addressed the precise nature of his hip problem. There is not one accepted diagnosis, but a very good source has told me Murray has a torn labrum. Any surgery would therefore be fraught with uncertainty and my understanding is that even if successful, the repair can sometimes have a limited shelf life.
Every condition is of course different, but Lleyton Hewitt had surgery on both hips for similar reasons in 2008 and 2010. He was never quite the same player again but still won three ATP titles after going under the knife for a second time.
Murray's other concern with surgery will be his extended absence from the sport. By July, he will have been missing for a whole year. However great a player, it is hugely challenging to rediscover that competitive edge after such a long break from the tour.