The Cameroon international will travel to England and undergo a medical on Saturday ahead of a temporary switch to Upton Park.
Out-of-favour Barcelona midfielder Alex Song will fly to London on Friday to finalise a season-long loan move to West Ham.
The former Arsenal midfielder will hold talks with Hammers officials before undergoing a medical on Saturday ahead of a move that will see him return to the Premier League after a two-year absence.
Song is expected to replace Mohamed Diame at Upton Park, with both Hull City and Everton weighing up a possible move for the Senegal international.
West Ham appear to have seen off competition for Song's signature from Galatasaray, who wanted to sign the 26-year-old on a permanent deal.
Song joined Barcelona from Arsenal in a £15 million deal in the summer of 2012 but has failed to establish himself as a regular first-team starter in either midfield or defence at Camp Nou.
West Ham have already recruited Enner Valencia, Mauro Zarate, Cheikhou Kouyate, Diafra Sakho and Diego Poyet this summer.