Michail Antonio has picked up a knee injury on international duty with Jamaica and it has come as a major blow for the Hammers.
The forward’s injury has forced West Ham to now consider signing a striker in the January transfer window.
The squad are now light on attacking options and David Moyes also lost Gianluca Scamacca in the summer transfer window.
However, West Ham are also mindful of being within the limits of the Premier League’s financial fair play calculations.
The Hammers do not want to fall foul of the rules and suffer a similar predicament as Everton.
The Toffees have been docked ten points by an independent panel for breaking the Premier League’s profit and sustainability rules.
The east London club want to sign a striker but are also keen to make sure that they make financially prudent decisions.
They are wary of breaching Premier League’s financial rules after spending big for two successive summers.