London - Captain Vincent Kompany is a doubt for Manchester City as they prepare for Sunday's derby at Manchester United seeking to halt an alarming dip in form.
Kompany, who turned 29 on Friday, sustained a hamstring injury in the Premier League defeat to Crystal Palace on Monday.
"Vincent will be assessed for a problem he got last week," manager Manuel Pellegrini told a news conference on Friday.
"We will see tomorrow if he will play or not. It is always better to play with Kompany, but if he can't play, we have a squad."
City have lost three out of five Premier League games since the beginning of March, and have fallen to fourth in the table, nine points behind leaders Chelsea and one behind third-placed United.
It is the first time this season that City have been lower in the table than their neighbours.
Pellegrini - whose job is under threat, according to British media reports - would not say whether he believes his team can still overhaul Chelsea in the race for the title.
"All that is in my mind is just to think about winning the next game you play, and that is the derby against United," the Chilean told reporters.
"Never is a draw a good result. I understand we are not having the away results we want. 2015 is not a good year for us for this, but the motivation is to win, always."
He said he was not surprised that United have improved significantly under manager Louis van Gaal.
"Louis van Gaal's teams are offensive teams who try to win titles," Pellegrini said. "United bought a lot of very good players in the summer: (Angel) Di Maria, (Ander) Herrera, (Radamel) Falcao, (Juan) Mata the season before and (Daley) Blind.
"They bought a lot of very good players - the strange thing was why they weren't doing it before, but it's no surprise (they have improved).
"I don't like to compare - always when you make these comparisons, there are a lot of things you don't analyse."
Pellegrini confirmed that striker Wilfried Bony will miss the derby at Old Trafford with ankle and knee injuries.