Benfica have agreed a EUR1.5million deal with Barcelona to sign full-back Alejandro Grimaldo.
The Liga champions announced the news on Tuesday, citing a clause in the agreement that sees Barca retain a sell-on percentage.
Grimaldo, 20, has spent seven years at Camp Nou without making a first-team appearance, coming through the Catalan giants' famous La Masia academy.
He captains the club's B team, but endured a prolonged spell on the sidelines when he tore cruciate ligaments in February 2013.
Benfica won the Primeira Liga last season and Rui Vitoria's men, who will take on Zenit in the last 16 of the Champions League, sit third after 14 matches this term.
Barca's statement did not include a completion date for the transfer.