Bringing Aaron Cresswell into competition has been a priority for the club this window, with interest in Filip Kostic finally amounting to nothing earlier this summer.
However, a move for Emerson seems more realistic, with Chelsea keen to offload the 28-year-old and they would prefer it to be a permanent transfer rather than another loan move for the Italian, who spent last season at Lyon.
It is believed that a deal would likely cost around £13million, with Emerson still having two years left on his current contract at Chelsea.
West Ham have already splashed out £100m this summer, with Gianluca Scamacca, Nayef Aguerd and Maxwel Cornet among those brought in to help bolster an incredibly thin squad last season. Aguerd will miss the first two months of the campaign after having to undergo ankle surgery.
Despite those arrivals, Moyes insisted the club “need to do a lot more business” before the window closes on September 1. The West Ham boss is keen to sign a left-back, a centre-back and a central midfielder in the next two weeks.
It has been a slow start to the season for the Hammers, sitting 19th in the table after two games. A first loss to Manchester City was followed by Nottingham Forest who then edged Moyes’ side as Declan Rice missed a penalty and West Ham did everything but score on a frustrating afternoon.