Kevin De Bruyne will be sidelined for up to six weeks after the Manchester City star suffered knee ligament damage in Thursday's League Cup win against Fulham.
De Bruyne limped off in the closing minutes of City's 2-0 victory at the Etihad Stadium after falling awkwardly in a clash with Timothy Fosu-Mensah.
The 27-year-old had scans on Friday that revealed the left knee injury is serious enough that he is unlikely to be back in action until mid-December, although he does not require surgery.
"We are sad for him. Nobody likes to be injured. Unfortunately he is injured but fortunately it is not surgery," City manager Pep Guardiola told reporters on Friday.
De Bruyne only recently returned from a right knee problem that forced him to miss two months this season, limiting the Belgium international to five appearances.