Players with 4 or more years of experience are "Released" and they are free to sign with whatever team they choose.
Players with less than 4 years of experience are "Waived" and they are exposed to the wavier wire in which teams have an opportunity to claim said player based on this years draft order. If a player is claimed he must be immediately placed on the 53-man roster which means the team claiming the player must cut another player to make room for the player claimed.