David Silva is doubtful for Manchester City's derby clash with Manchester United on Sunday after suffering a knock last weekend.
Silva felt discomfort in the closing stages of Sunday's 2-1 victory over West Ham, a game in which Silva scored the Premier League leaders' late winner.
City announced on Monday that Silva would not be travelling to Kharkiv for the Champions League game against Shakhtar Donetsk on Wednesday because he was "not fully fit."
It was assumed this was a precautionary measure but manager Pep Guardiola has now revealed the 31-year-old, who signed a contract extension last week, is also in danger of missing the trip to Old Trafford.
Guardiola, speaking at his prematch news conference in Ukraine, said: "David had a little bit of problems in the last minutes. We made a test after the game and I don't know if he is able to play on Sunday, so that's why he stayed there, to recover in Manchester.''
Guardiola was asked for further clarification on the nature of the injury but was unwilling to elaborate.
He said: "It's something, something uncomfortable he felt in the last minutes, before the goal he felt something.''
After being asked again, Guardiola laughed and said: "Hopefully he can be fit for Sunday but it was too risky to play him [on Wednesday].''
City have nothing riding on Wednesday's game having already secured top spot in Group F with five successive victories. Sunday is more of a priority with City having the chance to extend their eight-point lead over their closest challengers at the top of the Premier League.