Liverpool manager Jurgen Klopp admitted on Friday that he is unsure whether they will be able to pick Brazilian pair Alisson Becker or Fabinho for this weekend's match against Leeds United.
The pair, plus Roberto Firmino - who is injured - were selected for the World Cup qualifiers in South America but Liverpool, like other Premier League clubs, refused permission for players to join-up.
Clubs said they were forced into the action if the matches involved travelling to countries on the UK's Covid-19 red list, due to the quarantine period involved on arrival back in the UK.
“Our players, if they come back then they have to quarantine 10 days in a random hotel, next to the airport probably, which is not good for any people who have to do that but for a professional football player, being 10 days in a hotel - with the food they get from there - you lose everything,” Klopp told the official club website.
“You lose muscle, you lose everything. It means 10 days in the hotel, coming back [and] needing pretty much 10 days to get on track again.”
Brazil football chiefs, though, have asked Fifa to invoke the five-day suspension rule for clubs not releasing their players that could also mean Leeds' attacker Raphinha misses the game at Elland Road on Sunday.
“I don't know what will happen at the weekend, to be honest,” Klopp admitted. “In this moment, we have to see what other people decide and then we will again accept that probably, do what people tell us and try to win a football game.
“We all know we are in the middle of a pandemic, which is difficult for all parts of life and for football it was difficult as well - we have a few more games to play than we have to play usually internationally.
“We had a summer break where all of a sudden somebody organised again a Copa America, where they could have played the games, for example, without playing a Copa America, which they had a year before.”
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A number of other clubs including Manchester City, Manchester United and Chelsea, are also affected in a situation that has left the players unsure of their position.
“It’s a difficult situation, because we want to defend our country, we want to play for the Brazilian team,” Liverpool midfielder Fabinho told ESPN Brasil.
“But I don’t think it’s just between club and national team. It’s a government rule, I don’t think the English FA could change that, I think.
“I believe that Fifa would not be able to change either, neither Conmebol [South American Football Confederation] nor the CBF [Brazilian Football Confederatrion].
“We players are in the middle of this kind of dispute, right, without much to do. Because it was a Premier League decision not to release us.
“And on the one hand, we even understand, because on the way back I would have to stay 10 days in a hotel. Maybe lose three games. And 10 days is enough for you to lose a game rhythm. So it’s hard.”