The Sun says Barca will launch a £25million bid for Mascherano as soon as Yaya Toure completes his move to Manchester City.
The Catalan giants want Liverpool's Argy ace to replace Ivory Coast star Toure at the heart of their midfield.
Mascherano was left frustrated last summer after former Kop boss Rafa Benitez blocked a £22m switch to Barca.
Benitez, now at Inter Milan, is also in the hunt for the man he signed for £18m in 2008.
But Mascherano, 26, would prefer a move to Spain, where he would link up with Argentina team-mate Leo Messi.