You mean “possibly.” If they have no symptoms, they’re fine.
A “Case” doesn’t mean they’re ill. Just means a positive test. Which could mean anything.
Read this from the NFL chief medical talking head from last week. He says asymptomatic cases NEVER transmit the disease. That’s why he says, as of last week, no more testing of vaxxed healthy players. According to this guy all those players testing positive must have had at least the sniffles.
https://www.espn.com/nfl/story/_/id/32930584/data-shows-asymptomatic-individuals-not-spreading-covid-19-nfl-chief-medical-officer-says