#1 Alvaro Odriozola

Barcelona only just signed Nelson Semedo last summer, so the point of signing another right-back doesn't really make sense at first glance. However, a deeper look will reveal the true reason for choosing Odriozola here.
Even after signing Nelson Semedo, Ernesto Valverde prefers Sergi Roberto at right-back instead of the Portuguese. While the Spaniard may be a good player on the right, he is still a midfielder and loves to play there.
As a result, Barcelona need another right-back to compete with Semedo. And the best option would have been Alvaro Odriozola. The Real Sociedad full-back is an incredibly talented player.
He might still be raw, but at Barcelona, he could have been refined while playing alongside some of the finest players in the world.