Kevin De Bruyne, Vincent Kompany and Fabian Delph are all out for Manchester City's squad for the Champions League clash with Celtic at Parkhead on Wednesday night.
Belgian duo Kompany and De Bruyne flew to Barcelona to see top surgeon Dr Ramon Cugat for treatment on respective groin and hamstring problems and could be out for three and a half weeks.
Delph should have recovered from his muscle injury in time for the Everton game after the international break while back-up keeper Angus Gunn could be out for a week to 10 days with a hip problem.