Player who is eligible to sign with any club or franchise
In professional sports, a free agent is a player or manager who is eligible to sign with other clubs or franchises; i.e., not under contract to any specific team. The term is also used in reference to a player who is under contract at present but who is allowed to solicit offers from other teams. In some circumstances, the free agent's options are limited by league rules. Free agency was severely restricted in many sports leagues, instead clubs had a reserve clause which allowed them to retain players indefinitely. Usage. Association football.
https://en.wikipedia.org/wiki/Free_agent