The provisional date for City's F.A Cup Fifth Round tie at home to either Sunderland or Fulham is Saturday 14 February 2015, while Phil Parkinson's men are due to travel to Orient's Matchroom Stadium three days later on Tuesday 17 February 2015.
With near neighbours Leeds United set to host Millwall on the Saturday (14 February) as well though, advice from West Yorkshire Police could see the date of City's cup tie against Sunderland or Fulham change.
Any potential movement with regards the date of City's fifth round tie could also have an impact on the date of the Orient fixture as well.
The club will confirm anything further to supporters officially when they are in a position to do so.