A yellow card in soccer is a disciplinary action that could have major consequences as a game unfolds.

Professional soccer games include one referee on the pitch and two assistant referees down either touchline. Together, the three officials must control the temperature of a match and hold players accountable for bad challenges or improper behavior.

The referees have three options to keep players in line over 90 minutes. A simple whistle or verbal warning is the least serious course of action while a red card is the harshest. Between the two, though, is a yellow card.

Here’s a breakdown of what a yellow card means in soccer, and just what infractions can lead to a caution from an official.

A yellow card in soccer serves as a warning. If a player commits a questionable challenge, blatantly stops an opponent on the counter attack, or uses unsportsmanlike language toward an official, then they will receive a yellow card.

The disciplinary action cautions the player against similar behavior in the future of the match. In fact, those on a yellow card must be extremely careful for the rest of the game (or however long they remain on the pitch), because two yellows in a single match result in an automatic red card and sending off.

Although everyone should aim to stay out of the referee’s book, sometimes taking a yellow card is strategic. In the dying seconds of a close game, a player might purposely commit a yellow-card offense to stop an opponent from progressing down the field or regaining possession. They can also take a yellow card for time wasting.

Managers, assistants, and substitutes can also receive yellow cards for inappropriate conduct on the touchline. As long as the cautioned party does not commit another offense, then the booking does not play a significant role in the contest.