I should note that I'm an android player.
OK so we can choose our 1st captain and 9 other VC (just in case the ebola virus hits your team lol) but really what does he do. He's never mentioned in the match or after the match and there is no sign indicating who the captain is during the game. I think the captain should have some qualities like his morale should always be high (that's one of the main duties of a captain IRL) and he should be able to influence a little bit his players during important matches, like a boost in morale, condition or possession. In my observation the team captain is just nominal and does nothing.