Manchester United have spent much of the summer chasing a new full-back, with Newcastle's Lewis Hall having been on the club's wishlist for some time.
According to Fabrizio Romano, United officials have spoken to Balde's camp in recent days as an alternative route to strengthening that position.
Balde is currently happy at Camp Nou after playing a key role in Barcelona's LaLiga title win last season, making 21 starts under Hansi Flick and featuring 42 times in all competitions.
He remains a key player for the Catalan club, though the recent return of Joao Cancelo on a free transfer, along with the presence of Gerard Martin, gives Barcelona strong competition at left-back regardless of what happens with the Spain international.
Hall, 21, is understood to be keen on a move to Old Trafford amid an uncertain period at Newcastle, who have sold a number of key players this summer. United's interest in the England international has been consistent throughout the window, even after being offered the chance to sign Arsenal's Myles Lewis-Skelly instead.
For now, Balde represents a fallback option rather than United's first choice, but with the Newcastle situation showing little sign of movement, the club appear willing to explore every avenue as they look to solve their left-back conundrum before the transfer deadline arrives.
Balde is under contract at Barcelona until the summer of 2028, and the club would demand a significant fee were they to sanction a sale, particularly given his importance to Hansi Flick's title-winning side last season.
United's current options at left-back are Luke Shaw and Patrick Dorgu, with Shaw's recurring injury problems over recent years a key factor behind the club's search for a younger alternative capable of sharing the position long-term.