Although soccer is a fast paced sport, it can also be a physical, contact sport. One of the most recognizable parts of any soccer match, the referees have the option to brandish one of two colored cards as a way to admonish players for exceptionally poor behavior during a match.
There are four types of penalty cards at the various levels of soccer:
As we already know, a foul is an infraction committed by a player that is signaled by one of the officials on the pitch. The most common types of fouls are physical player fouls, where one player made too much contact, illegal contact, with another player.
If the infraction goes beyond what constitutes a verbal warning, referees can give out one of several penalty cards to players during a game. Depending on the severity of the infraction, a player may be removed from the field.
Officials typically keep the cards, which are about the size of playing cards, in their shirt pockets.
If illegal contact is made, the referee has the ability to give that player a verbal warning. However, if the referee sees fit, he has the ability to stop the play and award the player who made the illegal foul a card.
Blue cards are less common in soccer. A blue card is reserved for misconduct in indoor soccer and is considered a level lower than a yellow card. Blue card situations include things like spitting on the turf, illegal substitutions, violating house safety rules or committing minor physical fouls. It's up to the official to determine the difference between blue and yellow card offenses.
The consequence of a blue card is a penalty timeout that gives the offended team a two-minute power play advantage. The offending player sits in a penalty box and their team plays one person short until either a goal is scored against them or the two minutes runs out. This is very similar to a power-play situation in hockey.