Chairman David Sullivan says captain Declan Rice has probably played his last game for West Ham after being "promised" he could leave this summer.
The 24-year-old England midfielder has been heavily linked with a move away from London Stadium.
Asked if Wednesday's Europa Conference League triumph over Fiorentina was Rice's last appearance, Sullivan told Talksport: "I think it has to be.
"We promised him he could go. He set his heart on going."
On Wednesday Rice became only the third West Ham captain to lift a trophy for the club, following in the footsteps of the great Bobby Moore, who lifted the Cup Winners' Cup in 1965, and club legend Billy Bonds, who led the Hammers to the FA Cup in 1975 and 1980.