Enzo Perez is reportedly in talks with Valencia over a £20m move away from Benfica.
The 28-year-old is widely regarded as one of the best talents in the Portuguese league, with his performances last season helping Benfica to a domestic treble.
However, according to O Jogo, Valencia have submitted a bid in the region of £20m for the Argentine midfielder, a figure that Benfica would find difficult to turn down.
Valencia, who last won La Liga in 2004, are expected to make a number of signings this summer after transfer funds were made available by new owner Peter Lim.