Full disclaimer: I actually have no clue about soccer. Despite my German heritage. :)
You know how a single player can ruin a team? You see it all the time in sports. Take a soccer team for example: Eleven players. Each one of them highly skilled with a very specific responsibility on the field and at the same time a shared goal and an understanding that each one of them will do whatever it takes to win (which often means to do things above and beyond their primary role). The moment a single player doesn’t deliver, when he doesn’t do his duties, the moment he plays for himself instead of for the team, the instance when he thinks someone else can take the hit — the team falls apart.
The very same is true for startups. The moment you have a single person on your team who doesn’t do what’s need to be done, who doesn’t play with the team, who doesn’t put the team ahead of himself — you lose.
It is your responsibility as the founder to make sure your team works well together. That you become one unit. That everyone has everyone else’s back. And that you weed out the ones who don’t. As they are pure poison. And don’t wait. It rarely (if ever) get’s better.