Chelsea boss Mauricio Pochettino says a good attitude is crucial from squad members.
Pochettino wants everyone rowing in the same direction.
He said: "The balance is the most important thing. Sometimes you get that balance with less than more.
"In the end, you can only play eleven players. And it's not that you can't manage that situation, the problem is players that aren't going to play, from where do they get the motivation to be strong every day in training?
"Sometimes players that are not involved yet need to be in the dynamic of the squad, it's normal that they are not going to bring good things. It's not going to be easy for them first, and not fair, and we then can't ask to be happy and bring good energy.
"It's why we can't blame players. We need to be clever, strong, and be right in our decision on the number if we have injuries or suspended players to compensate for. But it won't be so big because it will not be for the benefit of the team."