The Cottagers have agreed to pay £12m up front for the Argentine with a further £3m in add-ons.
However, the 29-year-old is yet to agree to the move despite the chance to double his salary to around £70,000-a-week at Craven Cottage.
Ocampos is reluctant having grown settled in Spain and will soon have the chance to play Champions League football after winning the Europa League in May.
Fulham believe they will ultimately get their man having switched their focus from Callum Hudson-Odoi after they failed to agree a fee with Chelsea.
The Cottagers are also chasing an additional striker and have sounded out Germany international Fullkrug.
The 30-year-old Werder Bremen frontman is one of a host of options being looked at including Flamengo’s Pedro, Atalanta’s Duvan Zapata and Paris Saint-Germain’s Hugo Ekitike.
Marco Silva also wants a midfielder, with Everton’s Alex Iwobi reportedly of interest, and is chasing a further full-back despite the £15m signing of Leicester City’s Timothy Castagne.
AC Milan’s Fode Ballo-Toure, Union Berlin’s Josip Juranovic and Southampton’s Kyle Walker-Peters are some of the additional defenders being discussed in west London.