Manchester City captain Vincent Kompany is likely to miss Wednesday's Champions League trip to Borussia Monchengladbach, while Yaya Toure is a major doubt.
Kompany was forced to sit out Saturday's 4-1 defeat to Tottenham due to a calf problem picked up in City's Champions League-opening defeat to Juventus.
Ivory Coast international Toure was replaced during the Premier League clash at White Hart Lane with what was later confirmed as a hamstring injury and Manuel Pellegrini does not expect either to be available for Wednesday.
"Yaya had some problem in his hamstring," Pellegrini said. "We don't know about the Champions League, we must wait until Monday to decide. We will see what the doctor says [about a scan]."
"I don't think so, we will see," he added when asked about whether Kompany would be fit.
"At the beginning he was fit to be at least on the bench but in the warm up he felt some problems in his calf. It was the calf problem from against Juventus, he has not recovered 100 per cent."
Willy Caballero endured a difficult game against Spurs but Pellegrini defended his decision to field the former Malaga man in place of Joe Hart, who has been nursing a knock.
"Joe had a problem with his back during the week and couldn't just work one day this week, so I decided Willy must play," the Chilean explained. "Joe for me was not 100 per cent, I play Willy."
