That's up to you as commish. You can put a deadline on when keepers have to be set and then you'll hit "clear non-keepers" and they'll (unselected players) move to the pool of players that can be drafted.
By default we'll only keep the keepers and then expunge the other players right before your scheduled Fleaflicker draft time. Each league runs differently. Preference on the league's end.
Running a Keeper league. When do non keepers get put back in the draft pool? At the end of the season? Before the draft next year? I am tryin and g to figure out when keepers need to be to set and how long we have to deliberate on which players we want to keep.