Andy Murray is in race against time to be fit for the Australian Open after pulling out of his only warm-up event with his hip injury.
The British No.1 played a one-set exhibition match in Abu Dhabi on Friday before deciding to fly Down Under to continue his preparations for the first Grand Slam of the season.
But the double Olympic champion has now withdrawn from the Brisbane International to leave serious doubts he will be fit for Melbourne on January 15.
Murray, 30, has not played a competitive match since limping out of Wimbledon and withdrew from the US Open at the last minute.
His failure to play in Brisbane means he will slip out of the world's top 16 and could now face world No.1 Rafa Nadal or defending champion Roger Federer as early as the third round in the Australian Open.
A statement from the Brisbane International said: "Two-time former champion Andy Murray has been forced to withdraw from the 2018 Brisbane International presented by Suncorp due to pain in his right hip.
"The No 2 seed announced his decision on Tuesday afternoon, but will stay in Brisbane as he works towards returning to the tennis circuit."
Speaking on Monday, Murray said: "I'll probably make some changes to my schedule this year.
"I'll certainly play less than I have in the past to give my body time to rest and recover.
"I would want to play as long as I could physically do it, and most of the players would feel the same way... giving yourself breaks, especially as you get older, is very important and something that I'll certainly be looking to do."
Murray continued: "My hip feels way better than it did at Wimbledon.
"At Wimbledon, I almost made the semi-finals. So if it's better than that, then that's positive.
"But playing the matches and getting used to that intensity again and how you recover from a match is what is important. And I'm hoping I'm going to be okay, but you never know for sure until you go through it."
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