Clubs will be allowed to make up to five substitutions per match from next term.
Any changes are permitted on three occasions during the game itself, with an additional opportunity to introduce players at half-time.
Matchday squads will also be enlarged, as up to nine substitutes can now be named on the teamsheet.
It marks a return to the rules which were in place during Project Restart in June and July 2020, when it was agreed changes were required to help players with their fitness after the first coronavirus lockdown.
United were one of the sides to make use of the tweak, utilising either four or five substitutes in all but two of our games following the resumption, as we rallied to secure a third-placed finish under Ole Gunnar Solskjaer.