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.
Tottenham Hotspur are in the same situation, as their second home game of the season at their new base of Wembley - against Burnley - is arranged for the same date as the rugby league Challenge Cup final.
West Ham's game will have to be moved as the athletics 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.