Kalou has battled with a hamstring injury throughout the tournament and faces a fitness test hours before the game in Libreville.
"We are concerned about him but he is showing signs of recovery. We'll see before the game but we hope to be able to play him because he is a major player in the team," Zahoui told a news conference.
"We are praying he will make it, the doctors are doing their best to get him fit."
Zahoui said his team were approaching the match with "serenity and humility," despite being overwhelming favourites.
"It's a difficult thing to be the favourites and when you play against a team who really have nothing to lose," he added.
"We had the same situation in the quarter-final against Equatorial Guinea and came close to disaster. We were too anxious in the first half of that game and it was only after we discussed it at half-time that the players were more composed.
"We know that Mali will play with great heart and all these predictions of the journalists mean nothing. Our objective remains to finish the tournament as the best in Africa and if we remain focus and determined then we can beat them."
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