Concussion Replacements will be available for the first time in all four professional domestic competitions in England this summer as the ECB has acceded to requests from the counties to put the safety of players ahead of initial fears that the system might be misused.
The change of policy is one of several significant changes to the Playing Conditions affecting the Specsavers County Championship, Royal London One-Day Cup, Vitality Blast and Kia Super League.
Dr Nick Peirce, the ECB's chief medical officer, has overseen ECB research into concussion in cricket for several years. "This is a change made in the interests of player safety and health," he said. "While concussion is not as common in cricket as in contact sports such as rugby, our research has shown an average of around 15-20 incidents in first and second team cricket during each of the last few seasons.
"We have already mitigated against this by making helmets meeting the latest safety standards mandatory, and improving the levels of training for umpires and other officials. Now the ECB Board have approved a proposal from the Cricket Committee that we go a step further - with that proposal reflecting a very strong view from first-class counties."
The previous refusal to allow a replacement player had caused tension within the county system. Coaches, in particular, felt that by emphasising player safety and withdrawing a player they were put at an unfair disadvantage for the rest of the game. The prospect that they might condemn themselves to defeat, with all the possible knock-on effects that might bring, was an outcome that rested more easily with some counties than others.
The ECB has now acted, with the safeguard that any decision whether a like-for-like replacement is permissible is left to a medical professional.
Peirce said: "This season, each team, home and away, at first and second team level, will have to be supported by a medical professional who is qualified to make judgements on possible concussion following a head-strike. They will initially have a five-minute period to make an on-field assessment, and if concerns remain, that assessment will continue off the field, as previously.
"At this stage, there is no Concussion Replacement - and there is no time limit on deciding whether or not the player can return to the match. "But if the medical professional feels that the player has or may have been concussed, they will notify the Cricket Liaison Officer present. It will then be down to the CLO to approve the concussed player's team's nomination of a replacement."
Alan Fordham, the ECB's head of cricket operations, added: "We appreciate that the phrase 'like for like' leaves a need for some flexibility and interpretation. We will take into account the cricket that remains to be played and will aim to replace the resource lost by the affected side - but not so much that they are advantaged.
"For example they would not gain permission for a specialist batsman to be replaced by a specialist bowler if they were bowling in the fourth innings, or for a fast bowler to be replaced by a spinner if that team were to be bowling later in the match."
The full Playing Conditions are published on the ECB website.