The Hammers have allegedly missed out on a number of attacking targets this summer, but they appear willing to meet Hernandez's £13m release clause.
According to Sky Sports News, the former Manchester United striker has said that he is looking for wages in the region of £140,000 per week, but West Ham are attempting to work out a pay structure which suits both parties.
It has been suggested that while the East London outfit do not want to meet Hernandez's demands on a weekly basis, they are willing to include attractive bonuses for the 29-year-old.
During his previous spell in England with United, Hernandez made the majority of his appearances from the bench but he has been in excellent form since moving to Leverkusen.
In two seasons, he has contributed 39 goals from 76 outings in all competitions.