A crestfallen Andy Murray withdrew at the last minute from the Brisbane International on Tuesday, then cast serious doubt on his immediate future when he revealed he is considering surgery to mend his troublesome right hip. His chances of playing in the Australian Open, less than a fortnight away, are negligible. After 12 years on the Tour, his career is very much in the balance.

The 30-year-old Scot – who returned from back surgery in 2016 to win a third grand slam title and a second Olympic gold medal – sounded irretrievably despondent as he contemplated abandoning the drawn-out rehabilitation programme that has failed to resolve the unspecified problem in his hip since he lost to Sam Querrey in five sets in the Wimbledon quarter-finals almost six months ago.

In a poignant message on Instagram – posted with a picture of himself as a small boy – Murray said: “I’ve obviously been going through a really difficult period with my hip for a long time and have sought counsel from a number of hip specialists. Having been recommended to treat my hip conservatively since the US Open, I have done everything asked of me from a rehab perspective and worked extremely hard to try to get back on the court competing.

“Having played practice sets here in Brisbane with some top players, unfortunately this hasn’t worked yet to get me to the level I would like, so I have to reassess my options. Obviously continuing rehab is one option and giving my hip more time to recover. Surgery is also an option but the chances of a successful outcome are not as high as I would like, which has made this my secondary option, and my hope has been to avoid that. However, this is something I may have to consider, but let’s hope not.”

Referring to the picture he chose to flag up his explanation, Murray said: “I choose this pic as the little kid inside me just wants to play tennis and compete. I genuinely miss it so much and I would give anything to be back out there. I didn’t realise until these last few months just how much I love this game. Every time I wake up from sleeping or napping, I hope that it’s better, and it’s quite demoralising when you get on the court it’s not at the level you need it to be to compete at this level.

“In the short term I’m going to be staying in Australia for the next couple of days to see if my hip settles down a bit and will decide by the weekend whether to stay out here or fly home to assess what I do next. Sorry for the long post but I wanted to keep everyone in the loop and get this off my chest as it’s really hurting inside. Hope to see you back on court soon.”

Quick Guide Andy Murray's annus horribilis Show February 2017: Murray endures shock fourth-round defeat against Mischa Zverev at Australian Open and on return home is diagnosed with shingles. Returns in Dubai after a month off and wins only title of season. March: Pulls out of Miami Open because of elbow problem and is unable to carry out several commitments after contracting flu. Out for six weeks, also missing Britain’s Davis Cup quarter-final against France. May: With his form on clay shaky, Murray is laid low by a heavy cold and cough before French Open. Recovers to reach semi-finals before losing against Stan Wawrinka. July: Murray is unable to practise four days before start of Wimbledon title defence after long-standing hip problem flares up. Declares himself fit and limps through five matches, but endures his joint earliest exit from SW19 in a decade, beaten by Sam Querrey in quarter-finals. August: Hip injury forces Murray to withdraw from Rogers Cup and Western & Southern Open. Rafael Nadal ousts him as world No1. Murray pulls out of US Open two days before the start, saying he is not fit enough to do himself justice. September Announces he is unlikely to play again in 2017 in order to undergo 'extended period of rest and rehabilitation'. Rules himself out of the ATP World Tour Finals in London.

January 2018 Pulls out of planned comeback at Brisbane International because of pain in right hip. Photograph: Darren England/AAP

The future for Murray seems as distant as the past as he struggles to acknowledge that the hard work he has put in to rebuild his career since his last match – on the ninth day of Wimbledon, where he has enjoyed his most sun-kissed moments – has yet to repay him even a slim dividend.

The former world No1, idling at No16 in the world rankings during his enforced sabbatical, insisted privately in the aftermath of Tuesday’s withdrawal that he was determined to play in Melbourne, where he has been a beaten finalist five times. That looks a forlorn hope.

Murray, striving to be positive in adversity, made similarly optimistic noises before leaving Abu Dhabi for Queensland last weekend. We should be under no illusion: the Scot is fighting for his career. He said when he arrived in Brisbane what he needed was match time, not more relentless rehab and practice. Those plans are in tatters.

Murray was due to resume competitive play against Ryan Harrison on Thursday, at a tournament where he had won all nine of his previous matches – but they were four and five years ago.

Kyle Edmund hit with him in London in early December and did not seem unduly surprised when he learned Murray had withdrawn from Brisbane. “No one really knows where he’s at, do they?” Edmund said of his friend and mentor after beating the Canadian Denis Shapovalov in three sets to advance to the next round.

And, if Murray’s coyness about the precise nature of his injury reveals anything, it is that he is increasingly worried about his future. He is not in denial, but his instinct is to “find a way” rather than dwell on the grimness of a predicament that threatens to rob him of the joy of hitting a tennis ball. Edmund added: “It’s a shame he’s not playing because he’s not ready. It sucks. Everyone wants him to be on court.”

While others can bang the drum for Murray, the player is a realist, and any sensible reading of his most recent pronouncements identifies his central concerns. “I just want to play,” he said plaintively. He acknowledges that returning to No1 in the world is not even a mid-term ambition; nor is winning the 2018 Australian Open anything more than fanciful.

Murray, it has to be acknowledged, is a 3 sitting duck for the game’s fitter, younger predators. For all that there were sparks of his old zip in his 2-6 loss to Roberto Bautista Agut in their one-set exhibition match in Abu Dhabi on Friday, it was hard to miss the stiffness of his limp and inability (or reluctance) to hunt down balls wide on his forehand side. As Neil Young wrote, Rust Never Sleeps.

Murray told the Guardian two years ago he envisaged playing at or near the highest level until he was 33 or 34. That forecast might need adjusting.

Even a generous assessment would not rate his chances of getting back to his best at more than even money. If he does – as he did so spectacularly after gambling on back surgery in 2013 – he will have surprised us all again. Then, he was away for only two and half months; this time, half a year has seemed an agonisingly long absence for a player whose love of the game is boundless.

Beyond argument, Murray is at a crossroads. If he plays at all in Melbourne it will be a result of sorts. If he plays well and loses, with no more than the expected match soreness, he will be encouraged to believe he has a chance of being competitive in the short-to-medium term. If he wins and progresses to the second week, the comeback will be up and running.

On the other hand, a heavy defeat or suffering physically more than he had anticipated could persuade him to swap sweltering Australia for the comforting fireside embrace of his young family in midwinter Oxshott. Right now, nobody knows which way this fight is going to go, not even Murray.