Leyton Orient have announced an unnamed first-team player has tested positive for coronavirus.
The League Two club revealed the individual had shown mild symptoms and was subsequently placed into self-isolation.
The first team have now entered a further seven days of self-isolation in line with government guidelines as a result of the positive test, which follows four such cases at Portsmouth.
"It is obviously a huge concern of everyone's that a case like this has been reported, and of course it is a worry that it has impacted one of our players and our club directly," said head coach Ross Embleton in a club statement.
"The positive for us is that the symptoms have not got any worse and the player in question is improving every day.
"It is vital that we continue to follow the guidelines and isolate for another week in order to give the virus the time to pass."
The suspension of all domestic football was extended until April 30 at the earliest last week due to the coronavirus pandemic.