Dolphins safety Michael Thomas is set to be a Restricted Free Agent this offseason. So the team has to decide whether to tender him or let him walk.
Any player who has an expiring contract who has three accrued seasons, but less than four accrued seasons, is considered a restricted free agent. An accrued season is any year in which a player is on the 53-man roster for at least six games.
A RFA is a player who has received a qualifying offer from his old club (negotiated in the CBA), but is free to look and negotiated with other clubs.