Tevez has been out with a hamstring injury for almost four weeks and is virtually certain to miss Saturday's trip to Everton.
The Argentina international is desperate to play against Stoke at Wembley but has so far managed to do only light training.
And the clock is now ticking, with Tevez needing to be involved against Spurs to stand any chance of featuring in City's first major final for 30 years.
"It is very difficult for him to play against Everton and if he doesn't play against Tottenham, it will be impossible for Carlos to play in the final," said Mancini.
Source: PA
Source: PA