Brazil defender Fabricio Bruno did not play in Flamengo's Copa Libertadores victory this week.
The stopper is set to become the first signing for new West Ham boss Julen Lopetegui.
He appears set to make a 15 million move to the east London club in the coming days.
Per The Standard, a deal has already been agreed between the player and the club.
Now both teams are negotiating the final terms of the transfer fee before finalizing his contract.
Bruno was an unused substitute in a 3-0 win for his team over Columbian outfit Millonarios.