Releasing a Player

Ok, so here is a silly question, because I am having a brain fart.  If I release a player from a team, at least in my mind, that player should go to the available players pool, correct?  In my league the player just disappears... They remain in the player DB, but don't show up in the available players list.  How would I get them into that list once they are released from a team?

Thanks!