The on-loan Rangers man becomes the fifth member of Kenny Jackett's squad to contract Covid-19 following the latest batch of tests the club received.
James Bolton, Andy Cannon, Haji Mnoga and Sean Raggett were all confirmed cases on Saturday.
McCrorie is now in self-isolation along with the aforementioned quartet.
A club statement read: ‘Portsmouth Football Club can confirm that Ross McCrorie has tested positive for coronavirus.
‘Previous tests showed that four other members of the squad – James Bolton, Andy Cannon, Haji Mnoga and Sean Raggett – had also contracted the virus.
‘All five players displayed mild or no symptoms, but are self-isolating in accordance with government guidelines.
‘The club are now waiting on the results of one more test, which is for a member of the backroom team.
‘We urge everyone to continue following government advice to help limit the spread of this virus.’