Guardiola is convinced this summer's Club World Cup campaign will take a toll on his players eventually into next season.
Ahead of meeting Al-Hilal in the round of 16, Guardiola said: "After this, let's see what happens. We can rest and take the time that the Premier League has allowed us to rest and then we will see.
"Maybe in November, December or January it will be a disaster, we are exhausted and the World Cup has destroyed us. I don't know but it's the first time in our lives that this has happened.
"Mentally I think in the past the players have played in World Cups or European Championships for their national teams so it happens sometimes. You need a rest mentally sometimes, you can recover and then we will see when we come back.
"But I try not to think about it otherwise I would get too anxious. Instead, I try to relax, enjoy the days here and the good vibes that we have. The most important thing is to recover to find within ourselves what we were. That's my main target in this tournament."