According to Martin Mosnier of Eurosport France (h/t Jack Otway of the Daily Express), Dembele is considering leaving BVB after just one season following manager Thomas Tuchel's dismissal, and Premier League pair United and Chelsea are also interested in signing him as well as the Blaugrana.
Dortmund sporting director Michael Zorc has said the youngster, who turned 20 in May, will not be for sale. Per Otway, he told German newspaper Waz: "Ousmane Dembele has a long-term contract [until 2021] and we are making definite plans with him. There are no negotiations [with Barca]. Ousmane is going to be playing for Dortmund in the coming season."
While the club are naturally hoping to keep hold of him, they might have a tough time after he enjoyed a sensational first season at the Westfalenstadion, in which he racked up 10 goals and 21 assists in all competitions.
The versatile winger split his time between both flanks and also played as a No. 10 for BVB, aided by his impressive ability with both feet, per Squawka Football:
Dembele has pace to burn and his direct running and neat footwork make him difficult for defenders to contain.
Bundesliga commentators Kevin Hatchard and Angus Torode hailed the youngster's potential when he put in a thrilling performance for France against England on June 13:
He would make an outstanding buy for any of the sides above, United and Barca in particular.
Barcelona have need of cover for Lionel Messi and Neymar, while his ability to play as a No. 10 could also see him take up an advanced role in midfield.
As for United, they need a serious injection of pace and creativity in the final third after mustering just 54 goals in the Premier League last term, so Dembele would be an excellent capture alongside a striker to finish off the chances he creates.
Landing him will be difficult for Barca given Dortmund's resistance to a move, and news of serious competition from the Premier League will only make it harder.
Meanwhile, according to Globo Esporte (h/t Sport), Santos playmaker Lucas Lima has confirmed he will join Barcelona on a free transfer in January, though he must wait until July 1 to sign a pre-contract with the Catalan giants.
Lima is said to have "confirmed his signing in a game of poker with Neymar in which 50 people were present."
According to Fox Sports Brazil (h/t Marca), Lima is in a relationship with Neymar's sister, Raffaela, and is represented by the Barcelona forward's father.
Football journalist Rafael Hernandez is unhappy with the prospect of Lima joining and noted he might not be quite the bargain he appears to be on a free transfer:
The 26-year-old has made 14 caps for Brazil's national side, but a record of just nine goals and 20 assists in 92 appearances for Santos won't be overly inspiring to many of the Camp Nou faithful.
Lima is skillful and technically adept so he could fit in at Barcelona, but there remains a significant question mark over his ability to step up to the required level.