Liverpool trio Thiago Alcantara, Naby Keita and Joel Matip are unlikely to be ready to face Danish champions FC Midtjylland on Tuesday.
Keita has missed three games after testing positive for coronavirus, with Thiago and Matip injured at Everton.
Boss Jurgen Klopp says they will "probably" miss the Reds' second Champions League group game.
"I said last week it would be day by day but I think it will be a few more days," said the German.
The Premier League champions received a boost at the weekend when goalkeeper Alisson returned from a collarbone injury to play in the 2-1 win against Sheffield United.