The Arsenal captain has rejected the overtures of Manchester United and has opted to join the Catalan giant having lost his place in the Gunners' starting lineup.
The Belgium international, who hasn’t featured in any of Arsenal’s preseason matches due to injury, has been unable to oust either Laurent Koscielny or Per Mertesacker in Wenger’s side since he lost his regular first team spot over 18 months ago.
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Vermaelen faced a straight choice between Manchester United and Barcelona and privately indicated in the last 24 hours that he would prefer to join the Catalan club.
United, which is in need of defensive reinforcements following the departures of club stalwarts Nemanja Vidic and Rio Ferdinand, has now admitted defeat in the race to sign a player whose Arsenal career has been plagued by a number of injury setbacks.
Wenger confirmed on Thursday that Manchester United was among a group of clubs which had registered an interest in the former Ajax defender but the Arsenal manager insisted he would rather sell the 28-year-old abroad than aid one of his potential title rivals.
Asked directly whether United had made an offer, Wenger said: “I think they could be in a group.
"We have offers from abroad and ideally I would rather sell him to a club abroad. We're in a position where it's difficult to stand in his way."
Barcelona is keen to bolster its back line ahead of a bid to reclaim the league title from Atletico Madrid and has identified Vermaelen - who made 21 appearances for the north Londoners last season - as a target ahead of the new season.