The Manchester City manager claims it is "unbelievable" that UEFA is allowing the Group D match to go ahead on the surface at the Arena Khimki and believes the match should be called off if the weather takes a turn for the worse.
CSKA have not played at home since August and took their last Champions League home game, against Viktoria Plzen, 400 miles away to St Petersburg.
Pellegrini said: "I think it is unbelievable that the most important competition of the world is allowed to play in this pitch. We must pray tomorrow. If it is raining I think it will be impossible to play."