Soccer Rules - Assistant Referees
Two assist ant referees are appointed whose duties, subject to the decision of the referee, are to indicate:
When the whole of the ball has passed out of the field of play.
Which side is entitled to a corner kick, goal kick or throw-in.
When a player may be penalised for being in an offside position.
When a substitution is requested.
When misconduct or any other incident has occurred out of the view of the referee.
When offences have been committed.
Whenever the assistants are closer to the action than the referee (this includes, in particular circumstances, offences committed in the penalty area).
Whether, at penalty kicks, the goalkeeper has moved forward before the ball has been kicked and if the ball has crossed the line.
The assistant referees also assist the referee to control the match in accordance with the Laws of the Game. In particular, they may enter the field of play to help control the 9.15m distance.
In the event of undue interference or improper conduct, the referee will relieve an assistant referee of his duties and make a report to the appropriate authorities.