UEFA sent a group of experts to inspect the pitch at CSKA's Arena Khimki after the Russian side were forced to play their last Champions League game against Viktoria Plzen in St Petersburg due to the surface being deemed unplayable following heavy rain.
The pitch passed the inspection, but Fernandinho fears the state of the surface may affect City's style of football in a game he deems as a must-win encounter following the defeat by Bayern Munich last time out.
"I am worried about the pitch because our team try to play with the ball on the deck and if you don't have a good pitch it could be very hard for us," said Fernandinho.
"Everybody has talked about the pitch being bad but I don't know. We will see when we train there.
"If the pitch is bad we may have to fight to win the game but that is no different to any other game - it is always a fight to win.
"We can't think about the draw, we need to go there to win. We play CSKA twice, back to back.
"We must win and if we do that and then beat them at home we will take a big step towards qualification."
Reports had suggested City would not be allowed to practise on the pitch the day before the game but those fears were dismissed with Manuel Pellegrini's men allowed to train on Tuesday night, Russian time, ahead of the contest.
CSKA Moscow v Man City is live from 4.30pm on Wednesday on Sky Sports 2HD