Napoli are closing in on Porto striker Jackson Martinez.
The Colombian is wanted by Napoli as a replacement for new PSG signing Edinson Cavani.
"Porto do not want to sell the player because he is too important for the team," agent Manuel Manzo told Antena 2 in Colombia.
"In order to have him, Napoli will have to pay the entire clause. In any case, negotiations are continuing and if an important proposal comes in then we'll take it into consideration.
"The offer from Napoli is not far from Porto's request, but right now the only option is to pay the clause."