Neymar does not yet have the maturity to be the leader of Brazil's national team, although he is improving, said former Selecao star Leonardo on Thursday.
Leonardo, who is currently the director of football at Paris Saint-Germain, told SporTV in Brazil that while the 23-year-old Neymar has played impressively with the national team, he has also been unable to control his emotions.
The Barcelona star was named captain of Dunga's side following the 2014 World Cup, but was dealt a four-match ban during Copa America for an on-pitch scuffle.
He was sent off following the group stage defeat to Colombia for an attempted head-butt of Jeison Murillo that sparked a melee, during which Colombia striker Carlos Bacca was also shown red.
"Neymar is a great player but he doesn't yet have the maturity to lead Brazil and take charge of a team," Leonardo said. "He was criticised a lot when he played in Brazil. He just wanted to have the ball and dribble so that he could score and make the difference.
"Now he has learned to play without the ball. I didn't think he would be able to do it, but it is a question of mentality," Leonardo said. "Before he couldn't shoot penalty kicks and now he is a great specialist. There are so many ways that players can improve."
Leonardo has previously been vocal in his criticism of the Barcelona forward.
Neymar is doubtful for Saturday's international friendly against Costa Rica in New Jersey because of a right knee knock.
The Barcelona star, who only recently recovered from mumps, left training earlier this week after 20 minutes due to an injury scare.
Saturday's game will mark Brazil's first fixture since losing on penalties to Paraguay in the quarterfinals of the Copa America earlier this summer.
Dunga's men, who take on the United States in another friendly next Wednesday, begin their 2018 World Cup qualifying campaign against Chile next month.