The Italian fullback has chosen to stay in London while the team embarks on their preseason tour of the United States.
West Ham's manager, Graham Potter, has advised Emerson to explore finding a new club that suits his needs.
As a replacement, the team has signed El Hadji Malick Diouf, a new player who will join the team for the upcoming season.
Emerson Palmieri made 31 appearances in the Premier League for West Ham last season.