UEFA have announced a series of rule changes for their club competitions including switching the kick-off times of games.
From next season, should a game from the last 16 onwards go to extra time, managers will get the opportunity to make a fourth replacement.
The law change follows the success of the change seen in the English FA Cup this season where sides are already permitted to get the added sub in extra-time.
That means in Champions League, Europa League and the European Super Cup matches, three subs will be permitted in normal time – with the fourth only available if the games go to extra-time.
And for the actual finals, UEFA have decided clubs can increase the number of players on the bench from 18 to 23 – giving managers the choice of up to 12 replacements to pick from.
European football’s governing body have also decided to make changes to the kick-off times in their competitions from next season.
Until now, all Champions League group matches have kicked-off at 9.45pm CAT other than games in countries like Russia where freezing temperatures have made that impossible.
But that system is being changed to introduce staggered kick-off times in the group stages in a similar way to how the Europa League has operated.
From next season matches in the group stages of both competitions will now start at either 5.55pm or 8pm GMT (7.55 pm or 10pm CAT).
All games from the last-16 round onwards will kick-off at 8pm (10 pm CAT).