Argentine international Marcos Rojo has impressed in Portugal and is said to be a target for Brendan Rodgers, but Napoli could make a move as well.
Rojo, who plays either as a left-back or a centre-back, won't come cheap and it is reported that he has a release clause set at £25m.
Whether a potential buyer would need to activate that clause to secure his services remains to be seen, but it is suspected that Sporting Lisbon would accept a more modest bid.
Liverpool have been tracking the Argentine international for some time and a number of sources have reported that a summer switch is on the cards.
Napoli have significant financial clout and are keen to add to a squad that fell just short of the Scudetto but managed to win the Coppa Italia this season.
Nonetheless, Rojo, who is under contract until 2016, would probably be out of Napoli's price range if they were forced to meet the recession clause.
There have also been suggestions that Napoli will wait for Liverpool to sign Rojo and then move for Daniel Agger, who may become surplus to requirements.