Inter have allegedly been working all off-season to bring Bayern Munich's Vidal to the San Siro, but Sport and Sky Sport Italia report that Barcelona have swooped in at the eleventh hour.
According to Sky Sport Italia, Vidal's move to Barca is "a step away" while Catalan outlet Sport claim the Blaugrana have 'a verbal agreement' with the 31-year-old midfielder.
Vidal was allegedly first approached by Barca as recently as a week ago, quickly reaching an agreement over his wages and a €30 million (A$47 million) transfer fee with Bayern.
The Chilean could fly to Barcelona "in the coming hours" for his medical.
Barca reportedly turned to him when their negotiations for Paris Saint-Germain's French midfielder Adrien Rabiot hit a stumbling block.
Inter's recent flirtation with a move for Real Madrid's Luka Modric possibly gifted Barca the window for former Juventus man Vidal.
Roma were aggrieved to have Bordeaux attacker Malcom stolen from under their noses by Barcelona just days ago, when they thought their deal for the Brazilian was already wrapped up.