Hughes is preparing to argue his case with football chiefs in Togo and the Ivory Coast to hang on to two of his players for as long as possible at the end of next month.
And if both countries stay in the competition to the latter stages, the pair could be away from Boxing Day to the end of January - missing 11 games for City.
Hughes said: "There's a suggestion there may be a preparation period that has to be factored in, which we are obviously aware of.
"There will be a number of communications between the associations in terms of the release date for British-based players.
"A lot of other leagues have a break over the festive period that allows them to meet up earlier.
"I think there will be an understanding we have a crucial period of the season coming up and that will be taken into account.
"It is a time of great relevance to this club in terms of the league and possibly the Carling Cup."