When a goalie has control of the ball with his hands, he cannot be challenged by an opponent. Furthermore, if the keeper looks to have possession of the ball, people are less likely to assault it. If you make any kind of harsh contact, it's quite simple to earn a straight red card (spikes to the body, knock to the head, etc).
However, keep in mind that goalkeepers can be tripped up from behind if they aren't looking out for such things. Also, if a player other than the goalkeeper contacts the ball with their hand, it is possible to issue a free kick or even a penalty kick if there is no opposing player within 10 yards of the ball.
In general, keepers can use their hands in self-defense, but they shouldn't be the first thing they reach for when trying to protect the ball. There are often simpler ways of dealing with opponents. For example, a keeper might want to go over the top and punch it away if someone is close by; or perhaps roll up their shirt and run into the center circle to stop the ball.
While holding the ball in his outstretched open hand, a goalie is regarded to be in control of the ball if it is between his hands or between his hand and any surface (e.g., ground, own body). If a goalkeeper is challenged while holding the ball, then he must choose one of three things to do: save the challenge by punching or kicking the opposing player; allow the opposing player to take the ball from him; or call for help.
Help can come from anywhere on the field. A forward may try to score by shooting at the goal, a defender may try to block the shot, or a midfielder may try to pull a referee toward the play. If a defender wishes to challenge the keeper, he must do so before the ball is kicked off; after that time has elapsed, he is too late.
A goalkeeper can always be helped by a teammate, even if he isn't directly involved in the challenge. For example, if the defending team sends more than one player toward the ball, they all count as separate challenges. This is because each player needs to be given their own opportunity to attempt a save. If they were considered to be one single entity, then the goalkeeper would not be able to make a decision about how to deal with each individual threat.
In addition to teammates, a goalkeeper can also seek assistance from officials.
When the goalie has possession of the ball, no opposing player may touch or kick it. Control is typically regarded when any portion of the goaltender touches the ball. Penalties for endangering the goalie can be severe, including a goal kick and a red card.
A goalie must be able to sprint short distances in all directions. From side to side, back and forth, and in the direction the ball is moving on its way to the goal,
When the goalie has possession of the ball, no opposing player may touch or kick it. Control is typically regarded when any portion of the goaltender touches the ball. Penalties for endangering the goalie can be severe, including a goal kick and a red card.
However, it is possible to agree with the referee that you do not want your goalkeeper touched, in which case they can play the ball as they see fit. If this happens, there should be no penalty given to either team.
In fact, it is not unusual for goalkeepers to control the ball without being penalized by simply kicking it into the air before taking charge of it again. This gives them time to think about their next move without being forced into action prematurely.
There have been cases where a goalkeeper has been injured while playing the ball (usually when they have been kicked), but these are extremely rare. It means that the goalkeeper has been hit with enough force to cause injury; often, this will result in them having to leave the field temporarily.
It is important to note that if any opposing player does touch the goalkeeper illegally, whether accidentally or on purpose, they will receive a direct free-kick. The only exception to this rule is if the goalkeeper bites or kicks an opponent; in this case there is a chance they will not be shown a second yellow card but instead a red one.
Because goalkeepers are the only players permitted to handle the ball during ordinary game play, being able to easily identify the goalkeeper aids in preventing incorrect announcements of illegal handballs. Although it has not been demonstrated, it is widely held that an attacker automatically shoots the ball at the brightest part of the goal. If this were true, then goalkeepers would have little reason to touch the ball.
The first official rule book for soccer (the game we know today) was written by Ebenezer Cobb Morrell of New York City in 1884. One of his rules stated that "the goalkeeper may handle the ball". This rule has remained largely unchanged since then.
Before the advent of artificial turf, most soccer stadiums did not have a surface that could be easily scuffed up by foot balls. Thus, the goalkeeper's role was important, because he could pass the ball safely to himself or others while protecting the area behind him with his body.
Today, all professional soccer games are played on some type of artificial surface, so there is less need for goalkeepers to handle the ball. However, amateur and youth soccer games often take place on grass fields, which are more difficult to manage than artificial surfaces. In these cases, goalkeepers do have a role in handling the ball because they need to make sure that it's safe for their teammates to receive passes from them.
If a goalie is shown a red card, the same thing occurs to everyone else on the field: they are ejected. The team is then reduced to ten players, and they must call in the replacement goalie to replace the expelled one, as well as re-arrange their formation. The same thing that occurs to any other red-carded player. This includes any teammates who were about to take a free kick or penalty kick.
There have been several cases where goalkeepers have been sent off but continued playing. In two of these cases, the keepers remained in the game despite being given a second yellow card (which results in a ban for the second time).
The first keeper to be sent off and still play was Billy Meredith in the 18th minute of a Division 1 match between Boston College and Holy Cross on 11 October 1990. As the ball was about to be delivered for Holy Cross's first penalty kick, someone from behind the goal yelled "Red", and a college student ran onto the field with a pistol and shot dead Meredith, just before he could reach the ball. The shooter was never found and was not punished by the police department. However, because it was determined that Meredith had not played his last actionable movement (lifting his hands above his head), he was able to continue participating in the game.
The second case occurred during a Division 1 match between Indiana and Ohio State on 15 November 1990 when Mike Cavanagh was sent off for raising his arm to block a penalty kick.