Pep Guardiola has suggested post-World Cup fatigue could have been a factor in the knee injury that has ruled out Manchester City star Kevin De Bruyne for around three months.
De Bruyne only returned to training at City last week, having had a break after helping Belgium finish third in Russia in July.
He played for the final 30 minutes last Sunday as Guardiola's side began their Premier League title defence with a 2-0 victory at Arsenal.
However, the midfielder then suffered a knee injury in training on Wednesday, and was spotted on crutches that night at the premiere of 'All Or Nothing', a documentary that features behind-the-scenes footage of City's title victory.
Guardiola expects De Bruyne to be fit again by the beginning of December, but acknowledges City will have a tough task dealing with his absence, just as they did when a knee injury ruled out left-back Benjamin Mendy for virtually the whole of last season.
"We never know. My opinion is that when you ask a lot of the players, over more than 11 months, then after he comes back, this (injury) can happen," Guardiola told reporters on Friday.
"Nobody knows, but I'm pretty sure this can influence it. When you are fresh here, fresh on your legs, it doesn't happen. Sometimes it can.
"It will be two or three months. We hope he can do as much as possible to get back and help us again.
"It will be a big miss like last season with Mendy. Last season, Kevin was outstanding and of course for him and his family, you never want this.
"It's part of the game for the players -- it's normal, they don't rest. It's a tough season, with short recovery times. They (the football authorities) say 'let's go' and we are in the competition.
"Human beings have a limit and sometimes these things happen.
"My advice to him now is to rest, take the holidays he didn't get in these two or three weeks, do it now. Then he'll start training and we'll be waiting for him with big arms."
- 'Right moment' -
De Bruyne's absence is set to give David Silva more opportunities to impress, with the Spain playmaker free to commit himself to club duties after announcing his international retirement on Monday.
Silva missed several matches last season to spend time with his son Mateo, who was seriously ill in hospital after being born prematurely.
Mateo was allowed to leave hospital in May, five months after being born, and his now recovering well.
"I'm glad for him. If he has decided to do that, it is because he feels it is the right moment. Congratulations to him," Guardiola said.
"He has played more than 100 games, winning two European Championships and one World Cup. He is one of the most fascinating, incredible players in the whole history of Spain.
"He decided. No one at Man City, and not myself, pushed him. The player has to feel it. He decided to rest a little bit more with his wife and his little boy, and play with us."
City are waiting to hear from Tottenham about where their Premier League match in London, scheduled for October 28, might be played.
White Hart Lane will not be ready, as it is still being rebuilt, and Wembley is hosting an NFL match that day.
Asked if City might reverse the fixtures, and switch October's game to the Etihad Stadium, Guardiola said: "I don't know -- I can only say, if that happened, then four of our final five matches of the season would be away.
"I think when you are maybe playing for the Premier League, four games away is a little bit different."