The Spanish outlet Sport have reported that the Red’s have made the ‘first formal offer’ for the Belgium international.
Vermaelen moved to Barcelona from Arsenal for £15m back in 2014, but has struggled to make an impact since joining.
The former Arsenal man has struggled with injuries and has made just 11 La Liga appearances during his time at the Nou Camp.
Besiktas have already held early talks with the Barcelona over the transfer of Vermaelen according to the Fanatik newspaper. The Black Eagles are looking to sign the former Arsenal man on a season long loan.
Besiktas at the top of the Premier League and are currently six points ahead of their Istanbul rivals Fenerbahce. Barcelona take on Real Betis in the Spanish league next weekend. Luis Enrique’s side recorded a 6-0 win over Sporting this week.