Europe's clubs are seeking urgent talks with FIFA after raising concerns over player safety at next month's Africa Cup of Nations.
The emergence of the omicron variant of Covid-19 has led to countries around the world reintroducing restrictions and travel bans, and may lead to a fresh dispute over player release for international duty next month.
The public health situation globally looks set to present a major challenge ahead of the African finals in Cameroon between January 9 and February 6 and the international windows elsewhere starting on January 24 and running to February 1 or 2.
The European Club Association (ECA) board expressed its "deep concerns" around player safety and welfare around the international matches early next year, "particularly in light of the worsening public health situation and the severe challenges faced during recent international windows".
An ECA statement added: "The board agreed to engage urgently with FIFA to ensure all necessary precautions are in place to protect players and club interests as the health situation continues to deteriorate in an alarming manner."
The ECA is understood to be desperate to avoid a repeat of the problems which surrounded the September international window.
At that time Premier League clubs refused to release players for duty in red-list countries, because at the time they would have been required to quarantine in a Government-approved hotel for 10 days on their return to the UK.
Four England-based Argentina internationals did report for their country, but their presence led to the abandonment of the World Cup qualifier against Brazil on September 5.
Brazilian health officials said the four - Aston Villa's Emiliano Martinez and Emiliano Buendia and Tottenham's Giovani Lo Celso and Cristian Romero - had breached local rules on quarantine, with the UK on Brazil's red list. The Villa pair had travelled with their club's permission - the Spurs duo had not.
Four countries - Brazil, Chile, Mexico and Paraguay - initially asked FIFA to bar players whose call-ups had been refused from playing for their clubs for a five-day period after the break, but ultimately dropped that demand.
For the October window, a new agreement was reached where fully vaccinated players were allowed to travel for international duty in red-list countries on the basis that they quarantined for 10 days at a club facility, only leaving isolation to train and play.
That agreement was criticised by Liverpool manager Jurgen Klopp, who said it was "not a real solution". The chief executive of the Professional Footballers' Association, Maheta Molango, called for the quarantine period to be halved to five days.
The ECA board also discussed FIFA's proposals for a biennial World Cup, with opposition to the plans described as "unanimous" - a position that represents over 240 clubs across the continent who provided three-quarters of all players present at the last World Cup in Russia in 2018.
It said the new international match calendars for men's and women's football must ensure the "right balance" between the club and international game, afford the necessary safeguards and protections to players which it said were "overlooked" in the current proposals and take into account the voice of club football and the ECA in any decisions taken.