Steve Clarke is expected to end his relationship with Chelsea next week and join Gianfranco Zola at West Ham.
Zola will be named as the Hammers' boss in the next 24 hours and will attempt to take Clarke away from SW6.
Clarke has a 14 year association at Chelsea - first as player and now coach.
He left the Bridge to join up with Ruud Gullit at Newcastle but the ill-fated venture turned sour and Clarke returned to the Blues.
In the past two years, Clarke, who moved through the coaching ranks at Chelsea was undermined as assistant by the presence of Ten henk Cate at the side of Avram Grant.
It was widely held that Clarke had showdown talks with the club's top brass but was persuaded to stay.
His loyalty will now be tested as Franco takes on his first senior managerial appointment.
He is currently assistant manager to the Italian U21 squad.