Harris stayed behind in Melbourne and didn’t join the team charter flight to Sydney as a precaution after he dined with Head two nights ago.However, a negative rapid test has now been followed up by a negative PCR result and it’s understood Harris will be free to come to Sydney on Saturday, most likely by car – after Australian bowling duo Mitchell Starc and Nathan Lyon also chose to take the highway on Thursday.Australia have called in Mitchell Marsh, Nic Maddinson and Josh Inglis in as emergency back-up amid fears Head may not prove to be the only positive if the trickle of cases that went through the England camp during the Melbourne Test match was anything to go by.Catch every moment of The Ashes live and ad-break free during play on Kayo. New to Kayo? Try 14-days free now.However, the trio also remained back in Melbourne until further notice as they have just come in from the BBL system and it’s possible they could also join Harris on the road.PCR tests of Australian players were taken earlier today and daily tests will likely be taken out between now and the rest of the series as officials try desperately to stop the spread on the day when the two teams arrived by separate charters in the city with 21,000 daily cases.Australia is not out of the woods yet with PCR results still coming in, but the fact Harris as a dinner companion of Head has returned a negative is a decent sign that the team could avoid mass disruption.Sources close to Head say he’s feeling understandably flat at having his breakthrough Ashes tour cut short – although he is asymptomatic and likely to be cleared to play in the fifth Test in Hobart on January 14.Usman Khawaja is set to take Head’s place in the line-up, although there could be more changes depending on the results of PCR tests that may all be back in by Saturday morning.Maddinson has been the form Sheffield Shield batter over recent years and it would be an incredible comeback story for the left-hander if he was to be recalled after last playing a couple of Tests in 2016.Marsh was the hero of the World Cup final for Australia and is the hottest hitter in the country right now, albeit with the white ball.Australia have all bases covered, with a back-up keeper in Inglis, and a stack of bowlers already in the squad, with leg-spinner Mitchell Swepson and returning quicks Jhye Richardson and Josh Hazlewood all possibly putting their hand up for selection.The Australian team was due to fly by charter early on Friday, only to be delayed by the positive result for Head.England have already been forced to leave their coach Chris Silverwood and three of his assistants back in Melbourne in isolation, while match referee and former Australian great David Boon is also out of the Test.It’s understood Head had dinner with Harris on Wednesday night – and a sensible approach was taken to not put Harris on the flight with teammates.However, in a team environment, it’s possible he wouldn’t be the only close contact.Head has his partner with him in Melbourne for his seven days of isolation.“As part of our testing procedures, we are PCR testing players, their families and our support staff daily. Unfortunately, Travis returned a positive COVID-19 result earlier today,” a CA spokesperson said.“Thankfully he is asymptomatic at this stage. We anticipate that he will be available to play in the fifth Ashes Test in Hobart.“We are grateful to our exceptional medical staff for all the work they have done throughout this series and we will continue to work with and support the players, their families and staff from both teams.”Australian medical staff was taking extra precautions on Friday, with players to separate out on the flight and of course wear masks and sanitise regularly.It’s yet to be determined when Harris might join his teammates in Sydney, although there is no immediate hurry with the Test not starting until Wednesday January 5.