Play me or I will share your weaknesses with your enemies
You didn't get him enough playing time at sectionals last year. You owe him for bringing over one of your best players. He runs down other team members thinking he can get more playing time. He just plain nags the shit out of you until you put him in the lineup. Yeah, that guy.
You hope for weak matches and good partners. Maybe a default at cities would come his way. Would that be enough? What about if he actually thinks he's good? The rest of the team literally holds their breath when he's serving in a tie breaker. At least he got to a tie breaker, maybe that will help down the line. But he knows about the secret path that would allow your enemies to overrun you so you can't just send him packing. The yearly trials and tribulations of captaining.
This is never a bigger issue than a three line event like tri-level. There is very little margin for error, particularly when everyone else has ringers too. There's an old saying that goes keep your friends close but your enemies closer. The hard part is you aren't really sure which he is, or which he will become. It's a day to day, week to week exercise and it changes constantly. And he holds a grudge.
How you handle this guy can effect your team long after the event is over.