West Ham United vice-chairman Karen Brady insists the landmark ruling regarding the Lassana Diarra case 'has got everybody worried'.
The European Court of Justice ruled on Friday some of FIFA's rules on player transfers are contrary to European Union legislation relating to competition and freedom of movement.
The judgment came after former France international Diarra legally challenged FIFA rules following a dispute with a club dating to a decade ago.
He argued FIFA's restrictions meant he was unable to find a new club after his contract with Russian club Lokomotiv Moscow was terminated in 2014.