He should go to a club where he is going to get the most game time, no point going to Barca to warm the bench if you can be playing week in week out for Liverpool. Vermaelen, Umtiti, Pique, Santos, Lenglet. Although Pique is 31 and Vermaelen 32, still dont see him getting many games.
Liverpool seem stocked for CB's, Lovren, VVD, Gomez, Matip, plus up and comers like Phillips. Maybe Spurs if they have the cash next window, they have three recognised CB's if Toby goes in the european window, and Foyth has never played an EPL game. Sanchez, Vertonghen, Foyth, with Dier able to play CB in a pinch, and Vertonghen 31 now, he could almost walk into that first team.