Sergio Aguero will miss Manchester City's Champions League quarter-final against Lyon on Saturday through injury, says boss Pep Guardiola.
The Argentina striker had surgery on his knee in Barcelona in June but had yet to be ruled out of the resumption of the Champions League.
However, Aguero, 32, has not joined his team-mates in Lisbon for the last-eight tie against French side Lyon.
"He is still in Barcelona making a recovery," said Guardiola.
The Spaniard said he did not know if Aguero would be fit for the remainder of the competition if City progress.
If City win they will play either Barcelona or Bayern Munich in the semi-final on Wednesday.
"Anything can happen, it is a knockout game, but we are ready," said Guardiola.
"The pressure will be there, but it will be for all the other teams."
Each tie in the 'final-eight' competition in Portugal will be played over one leg.
"It's quite different," said Guardiola. "When you play the first leg you have one eye on the second leg.
"But when we play FA Cup or Carabao Cup we are used to it. There are no second chances - you are either in or out. The approach is very different."
RB Leipzig will face Paris St-Germain in the first semi-final on Tuesday.