West Ham face the possibility of having to play their first three matches of the season away from home.
The club have confirmed their second fixture, scheduled to be at home to Southampton, will have to be rearranged due to the World Athletics Championships being held at the London Stadium.
The event takes place between August 5 and 13, so the stadium will not be back in 'football mode' in time for the Saints game on August 19.
The fixture could be reversed, meaning the Hammers would face three games on the road.