Villa, who beat Liverpool 7-2 at home in the Premier League earlier this season, are due to host Jurgen Klopp's team in one of the outstanding ties of the round.
The fixture was in doubt, with Villa facing the prospect of having to forfeit the tie completely if they could not meet the Football Association's minimum requirement of 14 fit players -- including youth-team players -- in order to play the Premier League champions.
Villa confirmed via a tweet that the match will go ahead and they will turn to their under-23 team.
In the 2019-20 Carabao Cup quarterfinal, Villa faced Liverpool's U23s, as the first team was in Qatar for the FIFA Club World Cup, and won 5-0.
The English Football Association had issued a statement on Thursday saying a final decision will be made on Friday.
"The Football Association and Aston Villa are working closely together to try to ensure that the club's Third Round Proper fixture with Liverpool can go ahead as planned at Villa Park tomorrow evening," the FA said.
"Final confirmation will be made tomorrow pending the results of additional COVID-19 testing."
In a statement earlier on Thursday, Villa said: "Aston Villa can confirm that the club has closed its Bodymoor Heath training ground after a significant coronavirus outbreak.
"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."
Due to an escalating rate in COVID-19 infections in the UK, Southampton's third round tie against Shrewsbury on Saturday has already been postponed because of an outbreak at the EFL League One club.
Attempts are being made to find another date to play the game before the cut-off point of Jan. 23 -- the date of the fourth round.
The congested fixture list has left Villa with little scope to rearrange the Liverpool game, though, due to the Birmingham-based club not having a spare date on their calendar between now and Jan. 23.