West Ham's club record signing Sebastien Haller has joined Ajax for around 22.5m euros (£20.25m).
The Hammers spent £45m on the striker in 2019 and he scored 14 goals in 54 games in all competitions.
The club's owners felt Haller did not fit the template manager David Moyes wanted, or that the 26-year-old had shown a desire to adjust to it.
Moyes has been told he can use the funds from the sale and it is likely a striker will be signed this month.
Bournemouth's Josh King, 28, is understood to be among a number of players on the Hammers' radar.