Clubs in the English Football League will have to name at least one "club-developed" player in their matchday squads from the start of the 2018-19 season.
In addition, they must increase the number of homegrown players on matchday team sheets from six to seven starting from next season, the new rules being agreed at an AGM in London following a meeting of all 72 EFL clubs on Thursday.
A club-developed player is one who has been with their current team for at least 12 months prior to the end of their Under-19 season, while a homegrown player is defined as a player who has been registered with an FA or FAW-affiliated club for three seasons prior to his 21st birthday.
EFL chief executive Shaun Harvey told Sky Sports News: "I hope this latest commitment made by our clubs is further evidence of the EFL taking the initiative in looking for practical and effective measures that can be introduced to help managers and coaches in the ongoing development of young players.
"It is imperative that we provide young players not only with a platform, but also with the belief that opportunities will be made available to progress from youth to senior football. I am confident that this decision will have a positive and lasting impact on the future of football in this country."
Should any club fail to name a club-developed player in their matchday squad, they will only be able to name six substitutes, rather than the normal allocation of seven.