UEFA have announced a change of rules to the method of payment for transfers.
It has been announced transfer fees are limited to being paid over the first five years of a player's contract.
The move arrives after Chelsea, under American owners Todd Boehly and Clearlake, had signed a number of players to extended deals. By structuring their payments long-term, it has allowed the Blues to stay within Financial Fair Play laws.
The new rule will not be applied retroactively.
UEFA say the new rules would ensure "equal treatment of all clubs and improve financial sustainability".