London - Manchester City defender Aymeric Laporte could be out of action for up to a month with a hamstring injury, manager Pep Guardiola confirmed on Friday.
The Frenchman was forced off in the first half of Wednesday's Champions League victory at Real Madrid - just his eighth appearance of an injury-ravaged season.
"He has a hamstring injury, so that is normally three weeks or one month, more or less," said Guardiola.
"We tried to avoid it but unfortunately it has happened after four or five months out and then going directly into a big game. It sometimes happens."
Laporte suffered a knee injury in late August and then suffered a setback on his return in January, keeping out for a further month.
The clash at the Bernabeu was just the third game of his latest comeback.
The 25-year-old has been sorely missed throughout a season in which City have failed to mount a strong defence of their Premier League title.
His injury could hamper their quest for silverware on other fronts. He will miss this weekend's League Cup final against Aston Villa and is unlikely to be back for the second leg against Real on March 17.
He will also miss an FA Cup tie at Sheffield Wednesday and a derby against Manchester United at Old Trafford.
Guardiola said: "It is tough but they have to overcome these situations. Life is not easy and always in the world the people who survive overcome the bad moments.
"The guys who don't play are guys who say they can't face it, 'the world is against me'. Injuries are the same.
"If you think, 'I am an unlucky guy', you will not improve. It is what it is. Accept it and work harder to come back in the best condition as possible."
City will go into Sunday's showpiece against relegation-threatened Aston Villa at Wembley on a high after being Real Madrid 2-1 in the first leg of their Champions League last-16 tie at the Bernabeu on Wednesday.
But Guardiola has no concerns about his players' focus.
"The night after Madrid we were calm and then Madrid was gone and we were thinking about Aston Villa, and soon we will be thinking about Sheffield Wednesday," he said.
Winger Leroy Sane, who has been out with a knee injury since the Community Shield in August, will step up his comeback bid with a game for the under-23s against Arsenal on Friday.
Guardiola is hoping to win the League Cup for a third year in succession. City are aiming for their fifth triumph in seven seasons.
The former Barcelona boss said: "I know how difficult it is to reach the final for everyone involved. You've done really well to reach it when playing every three or four days. It is a great achievement to get there but now we must try to win."