Centre-back: Gerard Piqué
If you're not a Barcelona fan, you may not like him for his vocal nature, but it would be criminal to not give Gerard Pique due praise for his performances for both club and country. He has been a permanent fixture in Barca's rearguard for quite some time now.
Although he has shown some signs of age catching up with him in recent past (much like any other human footballer), there is still gas left in him to last at least another season.
Centre-back: Clément Lenglet
Seeing Barcelona had a reliable backup to the Samuel Umtiti-Pique duo in Vermaelen, Clement Lenglet's signing last summer did raise a few questions. However, as things panned out last season, the questions were subsequently answered.
Samuel Umtiti's persistent knee problem gave the Frenchman a new lease of life as he went on to make 45 appearances in total in the entire season and will perhaps hold on to his berth for the foreseeable future.