The club have been working on a renewal offer for the La Masia graduate since the end of August, following his bold elevation into Hansi Flick's first team plans.
Negotiations have stepped up since the end of October, after being asked to cover a right-back due to an injury crisis, and all parties are confident over an agreement being close at hand.
Barcelona hope to have the deal wrapped up before December, with several rival clubs aware of his low €15 million release clause, as part of a non-first team contract.
His current deal is set to expire in 2028, and the extension will bring that on to 2031, but his advisers are requesting that be lowered to 2030.
One aspect that has been agreed upon is a sizeable wage increase for the versatile 20-year-old and a new exit clause in excess of €75 million.