Basketball Innovations considers any player who has not registered this season to be a fill in. This is regardless of whether or not they have been team members in past seasons. Registration means the player has submitted a completed registration form and paid the registration fee sometime between mid June 2023 and now.

Fill ins are only to be used by teams to avoid forfeits and to introduce new prospective players to the competition. Fill in players should be of similar or lesser ability to the players they replace.

In order to monitor who is filling in for teams, team organisers are required to have fill ins approved by the Competition Administrator or Court Manager before they participate in a game.