The Blues can close the gap on leaders Arsenal to two points if they record a second win of the campaign against the title favourites.
Despite wanting his players to be positive, Mourinho admits that it may not be possible against Manuel Pellegrini's free-scoring City.
"I want to attack them, I can tell you that. But maybe after 10 or 20 minutes you realise Jose isn't attacking. If I don't, it's because I can't. I don't know if other teams refuse to attack or if they can't do it," he told the club's official website.
"I hope it is a good game, and after that if Man City are much better than us and we can't express our game and our football, that's a different story."
Chelsea earned a 2-1 victory over City when the teams met at Stamford Bridge in October.