County cricket will use concussion substitutes this summer as the sport continues to strengthen its safeguarding against head injuries.
A like for like replacement will be allowed when a player suffers a serious head injury forcing him to retire.
The substitute will be allowed to take a full part in the match and to avoid manipulation of the regulations, the match referee (cricket liaison officer) will determine which player can be called up.
"This is a change made in the interests of player safety and health," said Dr Nick Peirce, the ECB's chief medical officer.
"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. 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."
The new playing regulations for county cricket announced on Wednesday will also include stricter misconduct sanctions to bring the professional game in line with club level. Punishment for misconduct will range from a five-run penalty to a player being sent off for the remainder of the match.
"Approximately 20 Level 1 or 2 offences in 2017 from about 700 matches reflects a good overall standard of behaviour but we are not complacent," said Alan Fordham, the ECB's head of cricket operations. "The new Laws are an opportunity to continue the good work and we are keen also to support the recreational game through applying the same Laws and hopefully setting a good example."
Mock fielding has also been outlawed. Players who attempt to deceive a batsman by pretending to field the ball will be punished with a five-run penalty against their team.