Chelsea and Liverpool's Champions League round of 16 ties could be moved to neutral venues as UEFA are reluctant to stand by European vaccination laws.
The Blues have been drawn with French champions Lille, while the Reds face two mouth-watering encounters with Scudetto holders Inter.
Professional sportspeople will be required to have a Covid passport in order to enter venues in France and Italy under new regulations set to come in, which could be a cause for concern due to the comparatively low levels of players vaccinated in England.
The Premier League revealed in December that 77% of top-flight players have been double-jabbed against coronavirus, while 84% had received at least one dose - rates which are considerably lower than professional sports leagues across the globe.
UEFA are not willing to make vaccination for players and staff compulsory, and current regulations state that as long as 13 players (including one goalkeeper) are available for selection, then the fixture must be fulfilled. However, in order to circumnavigate government-imposed vaccination restrictions, ties could be moved elsewhere.
Chelsea and Liverpool face each other in Premier League action on Sunday with both sides feeling the effects of the Omicron wave. Reds boss Jurgen Klopp has tested positive for Covid-19 and will miss the game, while the Blues have just about emerged on the other side of their own coronavirus woes, but with their title hopes fading away after a poor run of recent results.