Open age Blue vs Red. Blue only have a bare 11. 40 minutes in, nothing much happening when two players get into a bit of a heated exchange about a CAR offisde call (bet no-one has ever seen that before !). Quick word with the two of them seems to have nipped it in the bud. However a couple of minutes later, something else is clearly said between them well away from (I think deliberately) my earshot. That sets blue player off big time who heads for the sideline saying something like 'He's a headcase. I've got to go off or there will be trouble and I can't afford that'. Could almost see the red mist swirling around his head. I head over to the sideline where he has left the pitch and ask what's going on. He tells me what he reckons has been said and says he is coming off. I think for about half a second about a caution for leaving the field of play withoug permission, but think managing the situation is more important as that is going to set him and everyone else off. I make it clear he can substitute himself (although no sub to replace him), but he can't change his mind and come back on. He says fine and game continues. At half time, blue captain comes up to me and asks if he can persuade the player to come back on is that OK. I say no, he has substituted himslef and a substituted player can't come back on. He says that's not what has happened, he has suffered a mental injury and his treatment is a quiet minute on the sideline. These days we're not supposed to treat mental issues as less real than physical issues. I smile and say nice try, but his player made it clear this is as a substitution. No further debate, but it left me wondering whether if the player had asked to go off temporarily for a bit of a 'time out' due to a 'mental injury' caused by the confrontation, would I have let him ? Have reread the relevant Law word by word and I don't see anything that says that's not allowed, but also obviously not what anyone had in mind when writing it. What do others think ? I've seen in junior football plenty of times, but roll on roll off means it's easy to deal with. Also would anyone have cautioned ? I think I'd have had no end of trouble if I had, but is common sense a good enough reason not to in this kind of situation ?