But you can have the equally unfair situation where one team has 22 fit players rotating through the positions, while the other one only has 19. Not necessarily. You can also have players being encouraged to go flat out for longer, to spend longer at peak heartrates, because they know they can do that, come off for a rest, then go at peak workload again later. You're more likely to get injured, especially to pull muscles, going repeatedly at peak loads rather than trying to pace yourself. Rolling subs encourage athletes to repeatedly reach the point of exhaustion. Neither of these have to be a problem. Some sports have a concussion protocol, where a player can come off & be assessed for injury, then return to the field if deemed to be ok. That can easily happen for other injuries, too. Sports can frequently provide a better spectacle when players are tired. No reason that games have to be frequently interrupted for non-rolling subs. No reason that subbing needs to waste time. Both are a question of how the game does things, not an inherent benefit of rolling subs vs players only being allowed to sub off once. You could equally argue that rolling subs means many more substitutions happen during a soccer game, therefore even more time gets wasted. Again, this is nothing at all to do with subs. This is a peculiarity of soccer's timing system. Rugby has subs, everyone knows exactly how long is left on the clock. If hockey got rid of rolling subs, everyone would still know exactly how long is left. Aussie rules has rolling subs, spectators & players on the ground can know the end of quarter is close, but not exactly how many seconds are left. How the timing is displayed is independent of the substitution system. None of what you've put are reasons why rolling subs are inherently better. Nor are they inherently worse. You've put reasons why soccer should change its timing system from the silliness of someone holding a board up after 45 minutes and then everyone guessing exactly how long there is to go. You've put reasons why teams should be able to do something when someone is injured. But they can both be fixed without introducing rolling subs, and they won't automatically be fixed by introducing rolling subs. .