The paper had previously reported the youth graduate of La Masia's release clause is €40m - although this has not been confirmed - while Barca have no desire to negotiate.
Roberto played in defence for much of last season after the club failed to replace Dani Alves but after the singing of Nelson Semedo is expected to move back into midfield.
The midfielder in question being Sergi Roberto.
Roberto started 39 games in all competitions last season, netting one goal and chipping in with six assists.
The potential for the Spaniard to become surplus to requirements has not only alerted United to his potential availability before the window closes, but Chelsea are also interested.
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United is not alone in showing interest in the Spaniard, as fellow Premier League side Chelsea has inquired about Sergi Roberto, although the London-based club has not made a formal offer.
The report in Don Balon goes on to say that though Roberto has excelled as a first-choice right-back in the absence of Aleix Vidal last season, the 25-year-old midfielder's future is uncertain following the arrival of new manager Ernesto Valverde.
With new additions set to arrive at the Camp Nou, courtesy of the funds generated by the sale of Neymar, any club that triggers Roberto's buy-out clause in his contract, a figure of £36 million, could be successful in their quest to acquire the player.
Premier League rivals Chelsea and French champions Monaco are also keen to buy Roberto.