Andriy Yarmolenko and Fabian Balbuena will both require work permits to 
play for West Ham.
A deal for Dortmund winger Yarmolenko appears to be getting closer with his club confirming they are in advanced talks with another club for his sale and have given him permission to speak to that same club. The Ukrainian international should fulfil the criteria for an automatic work permit having played over 75% of internationals in the past 24 months. He has made 15 appearances from a maximum 17 over two years and only missed the two games through a foot injury. Ukraine is ranked 35th in FIFA world rankings and the FA scheme requires a ranking of 50 or under to qualify.
Fabián Balbuena from Brazilian side Corinthians requires a work permit as he is a Paraguayan by birth.
Paraguay has a FIFA world ranking of 32 but Balbuena has not played 75% of all International matches so it would have to go to FA appeal panel the grounds of exceptional talent. He has made the Paraguayan squad just four times in the last two years starting twice and an unused substitute twice.
Jean Michaël Seri is another player who could require a work permit should the Hammers sign him. The Ivory Coast international has made 16 appearances for his country since 2015. Ivory Coast has a world ranking of 68 so fall outside the automatic FA work permit criteria.