Arsenal vice-chairman David Dein and Chelsea chief executive Peter Kenyon have warned football's governing bodies against bringing in player quotas.
Dein and Kenyon put on a rare united front on the issue of quotas
Fifa and Uefa could bring in rules to boost home-grown players in teams.
"It runs right in the face of freedom of movement of workers," said Dein. "The courts will be very busy with it."
Kenyon said: "I'm all in favour of quotas per squad but if you start imposing how many you have to play in any 11, that's too prescriptive."
He added: "Quotas are going to happen, there is no doubt about that. But we have to make sure we don't kill an element of the game that has made us successful."
606 DEBATE: Your thoughts on player quotas
Arsenal manager Arsene Wenger has already voiced his concern over the possible introduction of rules which would see teams fielding at least six homegrown players in a match.
The six players would have to be eligible to play for the club's national association but Wenger believes it would harm the quality of football.