Spanish publication 'Marca' reports that the club's staff are currently working hard behind the scenes to ensure that Ernesto Valverde is able to strengthen his squad in the New Year.
Aside from in defence, where Barca are desperate to strengthen at all costs, the Catalan side are also keen to reinforce in the middle of the park and in the attacking positions.
Furthermore, the aforementioned source claims that Barca are keen on players that would be able to be registered for the Champions League, with four names immediately coming to mind.
The four players Barca have in their sights are: Nabil Fekir, Arthur, Mesut Ozil and Oscar.
Fekir and Arthur are thought to be Barca's first-choice targets, with the Lyon man thought to be available for in the region of €50m, whilst Gremio midfielder Arthur would set the Spanish giants back around €25m.
With Ozil out of contract in the summer, he very much remains an option for Valverde's side, with Barca having been long-term admirers of the German. Meanwhile, whilst the club are keeping close tabs on former Chelsea man Oscar, it is thought that his huge wages in the CSL would make a deal difficult to push through.