Barcelona coach Pep Guardiola insists he doesn't regard his central defensive pairing as untouchable.
"It's Mascherano's opinion, but they are not the first choice," insisted Guardiola.
"Everybody has to win their place on the pitch. Depending on each game, we try to get everybody involved, because I feel that's the best way forward and I have faith in all of them. I think they'll all carry on here this year, and the next."