Injury

When a player is injured, quickly check on them to see if they are seriously injured. Law 5 states that if a player is seriously injured, the referee will stop the game. How do you know when a player is seriously injured?

Usually head and abdominal injuries can be serious. You may not see any blood but if a player is not moving at all on the ground, you should suspect a serious injury. A player who rolls on the ground 6 times while looking at you and asking you to blow your whistle may make the scene look dramatic but does not mean they are seriously injured. 

Take a look at the video below. A blue attacker falls onto the ground after colliding with two opponents. The referee continued the game for 12 seconds, until the ball went out of touch. The referee MUST stop the game in this situation. Even if a team was about to score, just stop the game. Err on the side of caution.