<P> Common offences include tackling above the shoulders, collapsing a scrum, ruck or maul, not releasing the ball when on the ground, or being offside . The non-offending team has a number of options when awarded a penalty: a "tap" kick, when the ball is kicked a very short distance from hand, allowing the kicker to regather the ball and run with it; a punt, when the ball is kicked a long distance from hand, for field position; a place - kick, when the kicker will attempt to score a goal; or a scrum . Players may be sent off (signalled by a red card) or temporarily suspended ("sin - binned") for ten minutes (yellow card) for foul play or repeated infringements, and may not be replaced . </P> <P> Occasionally, infringements are not caught by the referee during the match and these may be "cited" by the citing commissioner after the match and have punishments (usually suspension for a number of weeks) imposed on the infringing player . </P> <P> During the match, players may be replaced (for injury) or substituted (for tactical reasons). A player who has been replaced may not rejoin play unless he was temporarily replaced to have bleeding controlled; a player who has been substituted may return temporarily, to replace a player who has a blood injury or has suffered a concussion, or permanently, if he is replacing a front - row forward . In international matches, eight replacements are allowed; in domestic or cross-border tournaments, at the discretion of the responsible national union (s), the number of replacements may be nominated to a maximum of eight, of whom three must be sufficiently trained and experienced to provide cover for the three front row positions . </P> <P> Prior to 2016, all substitutions, no matter the cause, counted against the limit during a match . In 2016, World Rugby changed the law so that substitutions made to replace a player deemed unable to continue due to foul play by the opposition would no longer count against the match limit . This change was introduced in January of that year in the Southern Hemisphere and June in the Northern Hemisphere . </P>

How many subs can you make in rugby union