The Belgium international is determined to leave Arsenal in the summer transfer window and is now set to decide between the two European powerhouses
Barcelona and Manchester United are locked in a two-way battle for Thomas Vermaelen with the Liga side having now lodged a bid for the Arsenal defender, Goal understands.
Louis van Gaal's United have been knocked back with previous enquiries over an €8 million offer but are continuing to push hard to secure a deal as they attempt to bolster their defence following the departures of Nemanja Vidic, Rio Ferdinand and Patrice Evra.
Vermaelen has refused to sign a new deal at Arsenal and has told the club he will not agree fresh terms.
The 28-year-old will leave the Gunners on a free transfer next summer, when his current contract with the north London club expires, if they force him to stay for the 2014-15 campaign.
Arsenal would be loath to lose the Belgium international for nothing and so are ready to sell but understandably would rather the player moved to Catalunya rather than follow former team-mate Robin van Persie to Old Trafford.
Barcelona have rekindled their interest in Vermaelen but United boss Van Gaal has made it clear to club officials since day one that he wants Arsenal's club captain to bolster his defence.
Vermaelen now has a straight decision between two of the biggest clubs in the world and it is expected that he will make his choice and inform his potential new employers later this week.
United remain confident they will land Vermaelen but Barcelona, who themselves will be determined to improve in 2014-15 after a trophyless season last time out, believe they can persuade the former Ajax man to switch to La Liga.
Barca have already spent €20m on Jeremy Mathieu in a bid to bolster a lightweight defence already damaged by the retirement of Carles Puyol, and Vermaelen would represent a useful further addition as head coach Luis Enrique plots a switch to a 3-2-3-2 formation.