Aon Monday morning.
The rest of the squad, who were all tested on Wednesday, returned negative tests.
Sport24 is aware of who the player is, but has respected his wishes not to be named.
He is one of the new additions to have joined the Cheetahs during the coronavirus lockdown period and, as a result, has not been in any contact with any of the other players.
The Cheetahs are tentatively scheduled to take on the Southern Kings in back-to-back PRO14 fixtures on 22 August and 29 August as the competition resumes following the global lockdown.
Given that the South African government is yet to give the country's sides the final green light to return to training, playing those fixtures - one in Bloemfontein and one in Port Elizabeth - seems highly unlikely at this point.
- Compiled by Lloyd Burnard