Football's lawmakers have approved a temporary rule change that will allow each side up to five substitutes per match, while opening up the prospect for the controversial video assistant referee system to be suspended.
Proposals to allow an additional two substitutes were put forward by FIFA in order to protect player welfare when football resumes amid the coronavirus pandemic, and the International Football Association Board has given the idea an immediate green light.
The IFAB, which is made up of the four UK associations and world governing body FIFA, says each side will have only three opportunities, excluding half-time, to make changes in an amendment which will be allowed in all competitions that finish before the end of 2020.
All major European leagues have been suspended for several weeks, but a number are still hoping to complete the 2019-20 season, which will almost certainly involve fixtures being crammed into a slim timeframe.
A FIFA statement read: "As football begins to consider resumption of competitions across the world following the Covid-19 pandemic, the International Football Association Board (The IFAB) has agreed to make a temporary amendment to the laws of the game based on a proposal received from FIFA seeking to protect player welfare.
"For competitions which have either started or are intended to start, but are scheduled to be completed by 31 December 2020, the IFAB has approved FIFA's proposal to introduce a temporary amendment to Law 3 - The Players, which will allow for a maximum of five substitutes to be made per team.
"However, to avoid disruption to the game, each team will only have three opportunities to make substitutions; substitutions may also be made at half-time.
"The temporary amendment comes into force with immediate effect, and has been made as matches may be played in a condensed period in different weather conditions, both of which could have impacts on player welfare.
"The decision on whether to apply this temporary amendment will remain at the discretion of each individual competition organiser, while The IFAB and FIFA will determine at a later stage whether this temporary amendment would need to be extended further (e.g. for competitions due to be completed in 2021).
"The amendment to Law 3 affects both the 2019/20 and 2020/21 Laws of the Game, with the latter coming into effect as from 1 June 2020."
VAR was introduced in the Premier League at the start of the 2019-20 season, but has been widely criticised amid a plethora of controversial decisions.
FIFA says the system could be discontinued upon football's restart, but that decision would rest with each competition's governing bodies.
The statement concluded: "In relation to competitions in which the video assistant referee (VAR) system is implemented, these competitions are permitted to cease its use upon restart at the discretion of each individual competition organiser.
"However, where VAR is used, all aspects of the laws of the game and, by extension, the VAR protocol will remain in place."