The transfer window in English has been closed but the Italian teams can buy and sell players until the end of the month.
Fernandes has had little impact in East London since signing with FC Sion in 2016.
He made only 14 appearances in the Premier League last season and is now considered a surplus to the requirements.
The Hammers have already done business with Fiorentina in recent days.
"West Ham boss Manuel Pellegrini looks ready to download Edimilson Fernandes"
The failure of Aston Villa Carlos Sanchez signed a two-year contract at the London Stadium.
"I am very happy to be here, I am very excited and eager to achieve many," said Sanchez.
"I decided to come here because, first, it's the Premier League, second, it's a beautiful club and the fans always help the club and, third, for me it's an incredible opportunity and an incredible project that the club is leading, being ambitious and with desire to achieve good things.
"I would like to thank all the people, the whole club, for having me."
Sánchez spent two years in Villa before moving to Italy.
The 32-year-old says he is delighted to return to the Premier League.
"I always dreamed of playing in the Premier League."
"Previously, at Aston Villa, we started very well, but unfortunately it did not end well.
"But I always had the same desire to return and here I am, with the same mission, with the same desire and dream, and I am very grateful to everyone at West Ham."
Manuel Pellegrini needs to download players who have gone crazy this summer.
Felipe Anderson was replaced by Lazio, heavyweight Serie A, for around £ 48 million.
Fabian Balbuena, Ryan Fredericks, Lukasz Fabianski, Issa Diop, Jack Wilshere, Andriy Yarmolenko and Lucas Perez at the London Stadium.