Heavy rainfall on Saturday has led to flooding in Milan and Kovac has serious doubts as to whether the clash between his Group H leaders and second-placed Italy will go ahead.
"If the turf remains in these conditions, then I don't think the game can go ahead," Kovac told reporters.
"It would be like a game of water polo. The ball simply does not bounce. It will have to be called off if the pitch doesn't improve."
Both nations have won all three qualifiers so far and Kovac has spoken of his respect for Italy coach Antonio Conte.
"Italy are a strong team, even if they are missing some important elements," Kovac added.
"Playing at San Siro, we certainly cannot be considered favourites. In any case, we will try to earn at least a point.
"I respect Conte and compliment him, because he has been able to win everything as a player and as a Coach won three Scudetti in a row. He deserves the utmost respect.
"You can already see his influence on the Italy team and the significant changes he enacted. We were both players who contained opponents and maintained that tactical prudence into our new careers, he with a 3-5-2 and I with 4-4-2.
"We both put a lot of importance on to the defence, but that doesn't mean we won’t attack. We are quite similar as tacticians.
"I won't give my line-up, as this is not a friendly. I am sure Conte won't announce his starting XI beforehand either. I have no doubts and everything is prepared, but I am not going to tell you what my plans are."
