Registration of Free Players
Notwithstanding the above, football clubs are allowed to register free players outside of the transfer windows. Article 6.1. of FIFA RSTP expressly stipulates that “a professional whose contract has expired prior to the end of a registration period may be registered outside that registration period”.
This exception is only applicable to professional players and to those whose contracts have expired (or been terminated) prior to a registration period. It is important to observe that national associations must give due consideration to the sporting integrity of competitions. Accordingly, national associations may fix a deadline for the registration of free players outside of a transfer window. In particular, it is common to see a prohibition to register players in the last rounds of a competition league (for example, within the last five or ten matches).
It is also important to clarify that if a professional player terminates his contract, for whatever reason, after the end of a registration period, he will not able to register with another club before the next registration period.