Michael Essien will be unavailable when Real Madrid take on Manchester City in Wednesday's Champions League Group D match.The Ghanaian is out injured but coach Jose Mourinho not reveal the nature of the injury."He has a physical problem and did not recover in time to travel," Mourinho told a news conference without elaborating.After four of six matches, Real are second on seven points in what many consider the toughest group of Europe's elite club competition, one behind German champions Borussia Dortmund.Ajax Amsterdam are third on four points and City have only a slim chance of making it through to the last 16 with two points in fourth and last place.