West Ham were due to open the Olympic Stadium, venue of the 2012 London Games, with a prestige friendly against Italian champions Juventus on Aug. 7.
However, they are now due to play their first game at the 60,000-seater ground on July 28 in the first leg of their third qualifying round tie, although the Premier League club have asked if they can play the second leg at home on Aug. 4 instead.
"The club have today (Friday) made official representation to request that the fixture be reversed," West Ham said in a statement on their website (www.whufc.com).
"If successful, Shakhtyor Soligorsk of Belarus or NK Domzale of Slovenia will visit Queen Elizabeth Olympic Park for the return leg on Thursday 4 August."
West Ham, who finished seventh in the league last season, left their historic home, also known as the Boleyn Ground, at the end of the campaign having been there since 1904.
(Reporting by Ian Rodricks in Bengaluru; Editing by Ken Ferris)
