The Argentina international injured a hamstring in Monday night'sdefeat to Liverpool at Anfield and will be out until nextmonth, manager Roberto Mancini confirmed.
Tevez was already certain to miss Saturday's FA Cup semi-final against Manchester United at Wembley, but Mancini revealed the full extent of the injury.
Night to forget: Carlos Tevez limped off early in City's crushing defeat at Liverpool on Monday
'Tevez is not available for Saturday,' Mancini said. 'I think he will recover in three or four weeks. It is a big problem but we can't take any risks.'
It is a major issue for City given Tevez is by far their most prolific striker.
'It is a big problem,' said Mancini. 'But we can't take any risks. We have six games left and hopefully we can get Carlos back for the last two or three games.'
It means Tevez would be in with a chance of making the final on May 14 if City make it through to face either Stoke or Bolton.
Under pressure: Roberto Mancini's (right) fate is now in the hands of stand-in strikers Dzeko and Balotelli
However, Mancini will be forced to rely on either or both of Edin Dzeko and Mario Balotelli to derail United's Treble bid.
'I still have to decide what to do,' said Mancini. 'But both players know this is an important chance for them. Every player knows this is an important moment for the club. If we will we can go to a final, so every player will give 100 per cent.'
There is some good news for City though as full-back Micah Richards has returned to training and is expected to be fit after suffering a hamstring injury on England Under 21 duty at the end of last month.
'Micah Richards is available,' said Mancini. 'He trained two days ago and again yesterday. He will be okay.'
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