The Brazilian was missing from United's last two squads after a good performance against Paris Saint-Germain last midweek.
Now it has been confirmed a positive coronavirus test is the reason for Telles not being with the squad.
"He's been out now for a little while," Solskjaer told MUTV.
"He's tested positive for the coronavirus. But he has no symptoms; he's fine and we can't wait to get him back."
Telles will be hoping to rejoin the team as soon as his quarantine period is over.