Luiz Felipe Scolari believes Chelsea striker Didier Drogba will not return to the peak of his powers until mid-November.
He said: "Didier has not played for two months so it is difficult. He is not 100% ready. We need more time for Didier but he will grow with every game he plays and eventually reach the same levels as before.
"We will see Didier better than in the last game. He is doing his job very well but he needs more games and more time but I think he will need eight or 10 more games."
Chelsea - described as a "football machine" by Cluj striker Yssouf Kone - are aiming to dish out a stiff Champions League reality check to the Romanian double-winners.
Cluj produced a shock 2-1 victory away at Roma on their Champions League debut a fortnight ago and Wednesday night promises to be the biggest night in the club's 101-year history.
And Scolari was at pains to point out the qualities of a Cluj side packed with South Americans and Portuguese players, many of whom are familiar to him and have a point to prove.
"The attention of the world is not on Cluj, it is on Chelsea, but their players want to change that. They want to show the world they are good players and catch the eye of other clubs," said Scolari.
"I have shown my players a DVD about Cluj. If they win against Chelsea it is because they are better. It is not a surprise."
Coach Kone admitted ahead of what is perhaps the biggest night of Cluj's history: "I think Chelsea are four times stronger than Roma. When you play against them, you should run like crazy until the last minute. Chelsea are a football machine.
"In the end it's 11 against 11 and the pressure will be on Chelsea, not on us. If they beat us, it would be normal. If we beat them, it would be something fantastic."