Arek Milik is reported to have a €12m clause included in his contract with Marseille, where there are no clauses preventing his Serie A return.
Milik switched Napoli for Marseille in the January transfer window when the Ligue 1 side completed a loan move with an obligation to buy.
Marseille will pay €8m to secure the player’s services on a permanent deal adding €4m in add-ons.
According to Calciomercato.com, Milik has a €12m clause included in his contract with Marseille and a possible Serie A return is not being prevented by any clause included in his deal with the French club.
The Poland international had been linked with moves to Juventus and Roma in the last summer transfer window.
Milik refused to extend his expiring contract with Napoli with the club that decided to exclude the striker from the Serie A and UEFA lists for the first part of the campaign.