Sky Italia suggests that the 32-year-old attacking midfielder is wanted by the Serie A club as a replacement for Maxi Moralez who left for Mexican side Club Leon in December.
Diamanti is struggling for game time under Quique Sanchez Flores at Vicarage Road and is keen to return to Italy this month in a bid to resurrect his career.
The former West Ham United, Livorno, Brescia and Bologna man is on loan with the Hornets from Chinese Super League club Guangzhou Evergrande but is hoping to put himself in the frame for Antonio Conte's Italy squad for Euro2016 by returning to the Italian domestic league.
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