I hate when somebody makes a comment like that. "Oh, Tevez is out, we're gonna lose". Like with City now when they say "Oh Aguero is out, we'll lose".
Marchisio has been one of our better players this year. But he's not a vital point of our team and losing him doesn't damage us much IMO. Our biggest loss would be Tevez but even without him we can win (not talking specifically about this one).