Andre Ayew will play under a new manager after the international break following the sacking of Slaven Bilic.
Bilic's last game in charge was Saturday's 4-1 defeat by Liverpool at London Stadium.
A statement from West Ham said the club believed a change was necessary "to move forward positively and in line with their ambition."
Former Everton and Manchester United boss David Moyes has been strongly linked with succeeding Bilic.
West Ham say Bilic's coaching assistants Nikola Jurcevic, Edin Terzic, Julian Dicks and Miljenko Rak have also left the club with immediate effect.
"The club's search for a new manager to take West Ham United forward is under way and an announcement regarding Bilic's successor is expected to be made over the coming days," added the statement.