Adelaide, Dec 16 : Australia suffered a huge setback when skipper Pat Cummins was on Thursday ruled out of the second Ashes Test here after coming in contact with Covid positive person. The second Test, a day-night affair, is starting later on Thursday. Cummins had led Australia to a nine-wicket over arch-rivals England in the first Test at Brisbane. But he is out of the second Test after coming into contact with a person that has tested positive for the Covid-19 virus on Wednesday. Vice-captain Steve Smith will lead Australia in the second Test. Michael Neser will make his Test debut while Travis Head has been appointed as vice-captain for the Adelaide Test. "Gutted to miss this Test but really excited to see Neser finally get his chance in the baggy green. He has done the hard yards and is a seriously skillful player. Super frustrating but COVID has thrown us all some curveballs over the last couple of years. Will be cheering along!" Cummins tweeted on Thursday. South Australia Health has confirmed that Cummins is a close contact and will be required to isolate for seven days after the Australia captain went to dinner at an Adelaide restaurant where a fellow patron was identified as having the virus, cricket.com.au reported on Thursday. Under the current South Australia directives, arrivals from interstate must have a PCR test on arrival -- and are required to isolate until that test is taken -- but they are not required to isolate until they receive the result. Until last week, they had to isolate until they got their result. Cummins isolated as soon as he became aware of the situation and has since had a PCR test, which produced a negative result. He must now isolate for seven days. Cricket Australia confirmed Cummins did not breach any biosecurity protocols, and it is hoped he will be available to return to lead Australia for the Boxing Day Test at the MCG. "Cummins was dining in a restaurant last night and did not breach any bio-security protocols. He isolated as soon as he became aware of the situation and has since had a PCR test, which produced a negative result" Cricket Australia said in a statement on Thursday. "Mitchell Starc and Nathan Lyon were dining at the same restaurant as Cummins but at a separate table outdoors.SA Health has deemed them casual contacts and they are free to play (the Test)," Cricket Australia further said. Cummins's misfortune leaves Australia without arguably their best two fast bowlers, with Josh Hazlewood also missing the match with a side injury. Neser will become Australia's 462nd men's Test cricketer, while Smith will lead his country for the first time since the 2018 Cape Town Test against South Africa. The swift turn of events now sees Mitchell Starc and Nathan Lyon as the leaders of an Australian bowling attack featuring a third-gamer (Jhye Richardson) and a debutant (Michael Neser). /IANS