Premier League clubs could face sanctions from the world football governing body if they play South American players, who were not released for international duty, in this weekend's games.
Liverpool, Manchester United, Chelsea and Manchester City are among clubs who did not release Brazilian players for the current international break and face a choice of not selecting those players this weekend or running the risk of FIFA sanctions.
Sources have told Reuters that the Brazilian Football Federation (CBF) has triggered the "automatic restriction period" of five days which stops clubs from picking players who have not been released.
A CBF spokesman, however, said he was not aware of such a move.
Premier League clubs Wolves, Newcastle and Watford, along with Championship team Blackburn Rovers, could also lose players this weekend after the Chilean, Mexican and Paraguayan associations also activated the restriction period.
FIFA's rules state that any club selecting a player during the restriction period could face disciplinary action.
With South American countries on the red list for travel from the U.K. – meaning players would face hotel quarantine upon return to the country – the clubs chose not to release their players.
FIFA declined to comment. The Premier League and the Football Association (FA) were not immediately available for comment.
Liverpool would be without Alisson Becker, Fabinho and Roberto Firmino for its match at Leeds United on Sunday. The Yorkshire club would be without Raphinha.
Manchester City would be without goalkeeper Ederson and Gabriel Jesus against Leicester City on Saturday. Manchester United midfielder Fred and Chelsea defender Thiago Silva would also be impacted.
Players from Aston Villa and Tottenham Hotspur did feature for Argentina in their game against Brazil which was abandoned after five minutes on Sunday.
FIFA has opened disciplinary proceedings after Brazilian health authorities invaded the pitch to stop the game after accusing four of Argentina's English Premier League players of violating the country's COVID-19 quarantine rules.
Aston Villa goalkeeper Emiliano Martinez and Tottenham Hotspur duo Cristian Romero and Giovani Lo Celso were on the Neo Quimica Arena field as part of Argentina's team when officials from Brazil's health regulator Anvisa halted the match. Villa's Emiliano Buendia was in the stands.