Diafra Sakho looks likely to leave the London Stadium this month.
David Moyes is planning a re-shuffle of his team, adding balance to a squad which he believes has too many strikers and not enough midfielders.
The 28-year-old joined the Hammers in 2014 and has scored 24 goals in 71 outings for the club, but just four in all competitions this season.
It has been a poor year for West Ham's strikers, which adds a risk element to Sakho's potential sale. Summer signing Javier Hernandez has scored just four goals so far and has not found the net since October. Andre Ayew and Andy Carroll have just five goals between them, while Marko Arnautovic tops the club's scoring charts with five goals but he is not a natural number nine.
When fit and firing, Sakho is a handful and can be a clinical finisher, as he showed in his first season at West Ham where he scored 12 goals in 26 matches, and that is not the kind of record you want a striker of one of your rivals to be achieving.
Crystal Palace are level with Moyes' side on 22 points, two clear of the relegation zone. Palace have score just 20 league goals so far this term and only five teams have a poorer record than them.
Christian Benteke, their only senior striker, has scored just once so Sakho could be the man to take the pressure off him and, with the added game time compared to what he is getting a West Ham, he could well make the difference for the Eagles.
Should the form of Carroll, Ayew and Hernandez not improve then West Ham could quite easily slip back into trouble while a rival for relegation are benefiting from a player they willingly sent away.