I think this could work but maybe if the opposite team has the same opportunity (should they wish to swap out) to make it a fair option. I've been in many battles where someone didn't turn up due to real life issues or had to go unexpectedly, in fact had to do it myself due to loved one lying in hospital and felt awful I had to leave my crew a man down but family and health should always come first.

@ Myss

"wouldn't the players who wanted to play already be playing to begin with?"
. No. You might have 6 players that want to battle but might get matched in battle against 3.
"I just think it would be hard at times to find that alternate player.".
. You MIGHT not have or need an alternate player. But if something does happen this would at
. least give you an option to solve the problem.
.

I like the spirit of this idea.

To prevent from exploits by people taking shifts I would rather prefer that the other team is involved.

Like in a fair play settlement. You talk to the other team asking for a permission and any of their participant members could grant it.

I agree it would be nice, but wouldn't the players who wanted to play already be playing to begin with? Usually if they don't join they don't want to play unless it's just they can't be on long enough. I just think it would be hard at times to find that alternate player.

This would be really great for those of us that have debilitating conditions that can take us down at a moments notice. I have heart failure and sometimes I have to sit out at the last moment because I get sick - or mid battle I am suffering to stay in and present when I should be resting. I think this is a very good option.

also you could mke it so substitutes are only allowed if a persons score is zero