The Partenopei made the headlines throughout the summer with their spending spree, which saw them snap up the likes of Gonzalo Higauin and Jose Callejon.
Club president Aurelio De Laurentiis is determined to help the San Paolo outfit continue its growth by spending big in January.
Mascherano has been a regular at Barcelona this season but it is understood that he would seriously consider an offer from the Serie A giant.
Lamela, meanwhile, is De Laurentiis' dream, but the film tycoon is yet to contact either his entourage or Tottenham over a potential move.
Two other likely January signings are Luca Antonelli from Genoa, who will provide greater competition at left back, and Marco Borriello from Roma to become Higuain's backup.