"Villarreal and Porto have reached an agreement for the loan of forward Adrian Lopez, who will wear the yellow shirt until the end of the season subject to a medical and the signing of his contract, which will take place on Monday," Villarreal said in a statement on Saturday.
Lopez scored five goals in 23 appearances when on loan at Villarreal last season, including the winner in their Europa League semi-final first-leg win over Liverpool.
However, he has made just nine appearances in all competitions since returning to Porto at the start of the current campaign.