Manchester City manager Pep Guardiola has challenged his players to see squad rotation from his perspective, claiming the task of picking his starting XI "hurts a lot".
Premier League champions City have an embarrassment of riches when it comes to strength in depth, despite only adding Riyad Mahrez to their first-team squad during the close season.
At centre-back alone, Guardiola is blessed with four world-class options in the shape of Vincent Kompany, John Stones, Nicolas Otamendi and Aymeric Laporte.
But, put to Guardiola that he would face his biggest selection headache at the heart of his backline, he responded: "And the strikers and the midfielders as well.
"It's hard when you can't let some of them play. It hurts a lot.
"They don't know it. One day one of them will be a manager and will know how we feel.
"It's not comfortable, but if you want to compete in four competitions we cannot compete with just two good central defenders. We need four at the top level. They have to compete between each other and accept my rules.
"Today you don't play but tomorrow you're going to play and they have to be ready. It is what it is."
Guardiola opted to start Laporte and Stones for the 2-0 Community Shield win over Chelsea last weekend but says players who are left out over the course of the season must put all their effort into being ready for the next match.
"Of course in the last game Vincent didn't play or Nico didn't play. Are you telling me they didn't deserve to play? Of course they deserved to play, of course," Guardiola stressed.
"The same as John, the same as Aymeric.
"They don't deserve to play when they are lazy, they are not committed or they are not focused. Then we will have a problem. But that doesn't happen.
"I understand the situation, but after a game and regeneration in three days we have another game. Prepare for this one."
City kick off the defence of their Premier League title at Arsenal on Sunday.