The tie is scheduled for the weekend of January 28th/29th and with Birmingham based Aston Villa also being drawn at home to Blackburn Rovers, the clubs, the police and other agencies have to agree on which game is played on which day.
Any demands that may be required by the television companies with FA Broadcast Rights also have to be factored in to the equation before the date is officially confirmed.
If the game is on the Sunday then there is the possibilty that the scheduled home league game against Nottingham Forest, which is scheduled for February 1st, could be put back 24 hours.
City and Birmingham are also sorting out ticket prices and an announcement about this is expected in the coming days.
Match tickets have to be printed and delivered, so there is no point in contacting City's ticket office until an announcement is made by the club as to the selling arrangements.
It is looking like that if a replay is required, it will be at the Ricoh Arena on Tuesday February 8th but is still subject to confirmation.
More on this when it is available.