<P> Before a match, the two teams' captains toss a coin with the referee . The captain that wins the toss can decide to kick off or can choose which end of the field to defend . The captain that loses the toss then takes the other of the alternatives . </P> <P> The captain is often seen as responsible for a team's discipline . When a team persistently breaks the laws, the referee while issuing a caution will often speak with the team's captain to encourage them to improve their team's discipline . </P> <P> The captains are also traditionally responsible for appointing a substitute should a referee suffer an injury during a game, although in the professional game there are other procedures in place for dealing with this . </P>

How many players on the field in nrl