Preparations for the Australian Open are well underway with the qualifying rounds in Doha and Dubai complete, all of the biggest names in the game are due to descend on Melbourne for one of the highlights of the sporting calendar.The participation of Andy Murray in the event however has now been cast into doubt, as the former World Number 1 and three time Grand Slam champion has returned a positive test for COVID-19.Murray is believed to be asymptomatic and in good health but with travel restrictions at an all-time high, he now faces a race against time to get to Melbourne to complete his mandatory 14-day quarantine period.Following the protocolThe news that Murray has tested positive for COVID-19 comes tinged with irony, as the Scot opted not to travel to play at Delray Beach last week—for fears that he could come into contact with the virus on the move. He has been training hard in anticipation of the Australian Open, an event he has yet to win in his illustrious career and this news comes as the latest piece of bad fortune for the Scot’s on the court recently.Tennis Australia are believed to be doing all they can to get Murray to Melbourne and he will have access to regular testing but with the event due to start on Monday 8th February, he needs to return a negative test quickly.Wildcard AndyA chronic run of bad form with injury led Murray to intimate at the Australian Open in 2019 that he may be on the verge of retiring from top level tennis. Intensive hip surgery followed that year, and he has made tentative returns to the court ever since. His showing in Antwerp at the back end of 2019 gave his fans real cause for optimism but he has been unable to string results together consistently for the best part of two years.Consequently, Murray finds himself ranked 123 in the world and is requiring a wildcard to make the main draw in Melbourne. With such prestige within the game, there are very few that would begrudge Murray receiving a wildcard for an event he has been runner up in 5 times, but he will be all too aware that the chances for him at the very top level may be running out.How far can he go in Melbourne?Whilst there are huge question marks as to whether Murray will be able to get to Melbourne in time, he is set to participate in what looks to be a very open tournament. Smart money is of course on Novak Djokovic, the defending champion has won the Australian Open 8 times whilst Rafael Nadal will be looking to have his say.Elsewhere, US Open champion Dominic Thiem should be in the mix again whilst Stefanos Tsitsipas, Alexander Zverev and Daniil Medvedev shouldn’t be too far way either. Without being seeded, it looks a tall order for Murray, but all tennis fans will know better than to write the Scotsman off.