How are substitutes used?

Test cricket, unlike most team sports, does not have tactical substitutions.

The International Cricket Council (ICC), the sport's governing body, had introduced a 10-month trial in July 2005 to use tactical substitutions for one-day internationals only.

But after much criticism from players, commentators and fans, the trial was abandoned in March 2006.

For all other forms of the game, from Test right through to village cricket, replacements can be used as a substitute fielder or a runner with permission from the umpires.

SUBSTITUTE FIELDER

A fielding team can use a substitute fielder if one of their team has been injured during the course of a match.

But they cannot be used in specialist positions, which means they cannot bat, bowl or keep wicket.

If the substitute fielder hangs onto a catch, it will go down as "caught sub" in the scorebook.

However, a sub cannot be used if a player wants to leave the pitch to change their equipment.

That player cannot come back onto the field of play without the consent of the umpire, otherwise the umpire can penalise the fielding team five runs.

If that player has been off the pitch for more than 15 minutes, they cannot bowl for at least that length of time they were off the pitch.

Test match laws are slightly different as they come under the jurisdiction of the ICC.

Under Test match playing conditions, a player who has been absent from the field for more than eight minutes cannot bowl for the length of time they are absent.

They also cannot bat for at least that length of time for which they have been absent in the field or the start of their team's batting innings, unless their team have lost five wickets.

So if a player has been off the field for 20 minutes, they cannot bowl for at least 20 minutes from the point when they returned to the field.

However, these restrictions do not apply if the player has sustained an external blow (rather than an internal injury such as a pulled muscle) and has been forced to leave the field while playing the game.