Aston Villa closed their training ground on the eve of Friday's FA Cup third-round clash with Liverpool due to a "significant" coronavirus outbreak.
Villa on Thursday revealed a large number of first-team players and staff are isolating after testing positive for COVID-19 this week.
The first team did not train the day before they are due to face Premier League champions Liverpool at Villa Park and talks are being held over the scheduling of the tie.
"Aston Villa can confirm that the club has closed its Bodymoor Heath training ground after a significant coronavirus outbreak," a club statement said.
"A large number of first team players and staff returned positive tests after being routinely tested on Monday and immediately went into isolation.
"A second round of testing was carried out immediately and produced more positive results today.
"First team training ahead of tomorrow's FA Cup match with Liverpool was cancelled.
"Discussions are ongoing between medical representatives of the club, the Football Association and the Premier League."
The news comes after Southampton's third-round clash at Shrewsbury Town was called off as a result of a "significant" number of positive COVID-19 cases at the League One club.
Derby County this week revealed they will select a side made up of under-18 and under-23 players for their tie at non-League Chorley on Saturday, with interim boss Wayne Rooney and his first-team squad staying at home following a coronavirus outbreak at the Championship club.