Pjanic was sold by Juve to Barca this past summer.
“What still disappoints me to this day is that Sarri didn't trust his men and that disturbed me," Barcelona midfielder Pjanic told Tuttosport.
“The way he misjudged people remains the worst aspect, because every player in that locker room has always and will always give their all for the club and team.
“You might not get along with one or two, but that has never affected our efforts, because every player wants to win, because they are incredible professionals who want to pursue their objective.
“So, if a coach puts that into doubt, it means you don't have that alchemy that the President talked about."
He added: “Nobody is doubting Sarri's qualities as a coach, but there was this problem.
“At the end of the day, we still brought home another Scudetto, which must never be taken for granted."