The England captain, Michael Vaughan, will be able to use a substitute in future one-day matches after the International Cricket Council gave the green light yesterday to a set of proposals that are intended to spice up the shortened form of the game.
The changes will come into effect on 30 July, starting a 10-month trial. England and Australia, however, are keen to play under the new regulations immediately and there is a strong possibility that the NatWest Challenge, which starts on 7 July, will be the first tournament to employ them.
The ICC also approved raising the number of overs in which fielding restrictions apply from 15 to 20. Under the current rules a captain has to position nine fielders within the 30-yard circle during the first 15 overs of each game.
In future matches there will still be a 10-over period at the start of each game where fielding restrictions are compulsory, but the remaining 10 overs are to be used at the fielding captain's discretion in two five-over spells.
David Collier, the chief executive of the England and Wales Cricket Board, said: "We believe it is a positive proposal and something the crowds will enjoy. Spectators have been telling us that the middle period of one-day games are becoming predictable and this should help liven it up.
"The decision at the ICC chief executives' meeting was unanimous and we hope to be playing under these rules in the NatWest Challenge. It is in the best interest of everybody that we get used to the new regulations because the World Cup is less than two years away."
The ICC also agreed to conduct a further technology trial during the six-day Test match between Australia and the Rest of the World in October. The umpires will be allowed to refer decisions they are unsure about to a third umpire, who will use television replays to adjudicate.