Sky Sport Italia take note of the arrangement could be an loan with commitment to purchase toward the end of the season, hence spreading out the expense more than two years.
It's trusted the aggregate expense, including rewards, would come to around €28m.
Zaza could fly out to London tomorrow evening or on Friday morning for a therapeutic.
Hammers supervisor Slaven Bilic said Zaza was "a top player" and Sky Sport Italia assert the pair talked on the telephone today.
Napoli additionally stay intrigued, however seem, by all accounts, to be centering their vitality on a trade between Manolo Gabbiadini and Fiorentina striker Nikola Kalinic.