The captain is the most important member of the fielding side as he determines all the tactics including who should bowl (and how); and he is responsible for "setting the field", though usually in consultation with the bowler.
In all forms of cricket, if a fielder gets injured or becomes ill during a match, a substitute is allowed to field instead of him. The substitute cannot bowl, act as a captain or keep wicket. The substitute leaves the field when the injured player is fit to return.BattingMain articles: batsman and batting (cricket)W G Grace "taking guard" in 1883. His pads and bat are very similar to those used today. The gloves have evolved somewhat. Many modern players utilise more defensive equipment than was available to Grace, notably helmets and arm guards.
At any one time, there are two batsmen in the playing area. One takes station at the striker's end to defend the wicket as above and to score runs if possible. His partner, the non-striker, is at the end where the bowler is operating.
Batsmen come in to bat in a batting order, decided by the team captain. The first two batsmen – the "openers" – usually face the most hostile bowling from fresh fast bowlers with a new ball. The top batting positions are usually given to the most competent batsmen in the team, and the non-batsmen typically bat last. The pre-announced batting order is not mandatory and when a wicket falls any player who has not yet batted may be sent in next.