Manchester City's Vincent Kompany in Roma Fitness Race

Manchester City captain Vincent Kompany is facing a race against time to be fit for his side's decisive Champions League clash against Roma next week.

Manager Manuel Pellegrini has revealed the influential centre-back will definitely miss tonight's trip to Sunderland and the home game against Everton on Saturday with the hamstring injury he sustained at the weekend.

That could make him doubtful for next Wednesday's crucial final Group E game in Rome, when City's Champions League fate will be determined.

Pellegrini was still to learn the full extent of the problem when he held a press conference on Tuesday to preview the game at Sunderland.

The Chilean said: "It's very difficult because I cannot say without the opinion of the doctor how his injury will improve in the next days.

"It depends what degree of muscle injury he has. It's very difficult to know in this moment if he can play against Rome.

"He is not able to play against Sunderland or against Everton, that's sure.

"We'll see if he arrives against Roma. That will depend on the opinion of the doctor."

Kompany was injured in the closing minutes of the 3-0 Barclays Premier League win at Southampton on Sunday.

The 28-year-old's condition is a concern for the club given his importance to the team.

He has had a number of spells out with muscle injuries in recent seasons and his absence is often keenly felt.

This was evidenced last month when the Belgian missed the game at QPR with a calf problem and the team could only manage a 2-2 draw against the struggling Londoners.

Pellegrini will be anxious for him to recover in time to travel to the Italian capital, with City needing a positive result to have any chance of reaching the last 16.

Playmaker David Silva remains a doubt for that game as he battles to overcome a knee injury and midfielder Yaya Toure is suspended.

In the immediate short-term, his absence creates further problems as fellow centre-back Eliaquim Mangala is suspended for the Sunderland fixture after his sending-off at Southampton.

With the out-of-favor Matija Nastasic also injured, fringe player Dedryck Boyata or right-back Bacary Sagna could fill in.

Mangala has struggled to adapt to the English game since his B£32million summer move from Porto but Pellegrini retains faith.

He felt the Frenchman's dismissal, for a badly timed challenge on Shane Long when the score was 1-0 at St Mary's, may have shown an element of the player sacrificing himself.

Pellegrini said: "A lot of players need more time to settle in the Premier League because it's a difficult league.

"In the other sense, I don't think the foul that Mangala made was a good foul. Maybe it was a tactical foul or maybe he thought the player would score if he didn't get to the ball."