Reversing a Substitution?

Allegedly fourth Official put the wrong number up.

In general after a substitution is complete, can we allow it to be reversed up until the point play restarts?

May be more to the specific Neymar situation as my Portuguese isn't the best

I understand any decision can be changed if play hasn't restarted.

I also think there is possibly more to it than the post description.

EDIT: he was off the field receiving treatment at the time of the substitution and didnt notice it. Play restarted and it was the next stoppage when he wanted to return.

one said:

I understand any decision can be changed if play hasn't restarted.

I also think there is possibly more to it than the post description.

EDIT: he was off the field receiving treatment at the time of the substitution and didnt notice it. Play restarted and it was the next stoppage when he wanted to return.

Click to expand...

That applies to most laws but not substitutions as far as I can tell. Law 3, as below, is clear that the substitution is completed when a substitute enters the field of play and the replaced player becomes a substituted player. Unless repeat substitutions are in use I can't see any provision that it can be reversed.

The substitution is completed when a substitute enters the field of play; from that moment, the replaced player becomes a substituted player and the substitute becomes a player and can take any restart.

Let's not leave all the blame with the officials here. Yes, the 4O appears to have made a serious mistake. But why didn't the coaches immediately say something when the sign went up. Why didn't the sub go in call the guy who was supposed to come out? And why didn't the staff notice when the player who was supposed to be coming out didn't?

I do think it is an interesting scenario. If play had not re-started, I think we could fairly take the position that the substitution has been completed (i.e., the sub is now a player), but still ensure the player who was actually supposed to come off leaves rather than Neymar being excluded because the 4O held up the wrong number. (If Neymar had actually exited the field as part of the sub process, I think that would make it harder to justify.)