Manchester City striker Mario Balotelli is thought to be facing a battle to be fit ahead of Wednesday's Champions League match against Real Madrid.
City go into the game at the Etihad Stadium knowing that only a win will do if they are to keep alive their slim hopes of progressing in the competition.
However, Balotelli could miss the clash against the Spanish champions with a back problem, according to The Sun.
The Italian international has scored one goal in three European appearances for City so far this season.