Why do you think that?
Apart from the reality that he hasn't been regularly fit since his arrival in England 8 years ago, positionally naive - has relied on his pace & strength rather than properly reading the game. Yes, he can pass and tackle but a central defender for Pep has to be more than that. In the big matches, it was him who made the errors not the others in his defensive line.
I think it'll be a moot point in the end since he is unlikely to stay healthy but the fact that he has to focus on rehabilitating rather than learning Pep's very intricate game who relies very dearly on a particular profile CB does not bode well for the future