Aston Villa have experienced a "significant" coronavirus outbreak at the club on the eve of their FA Cup third-round tie with Liverpool, reports BBC Sport.
The Premier League side said a large number of first-team players and staff are in isolation after returning positive tests on Monday.
The club's training ground was closed on Thursday after a second round of testing produced more positive results.
Dean Smith's side are scheduled to face Liverpool at 19:45 GMT on Friday night.
"Discussions are ongoing between medical representatives of the club, the Football Association and the Premier League," Villa said in a statement.