Paris Saint-Germain forward Neymar is doubtful for Brazil's opening World Cup 2022 qualifier against Bolivia with a back injury.

Footage on social media this week showed Neymar putting his hand on his lower back and keeling on the floor in pain during a training session.

He was unable to train on Thursday and Tite is now preparing to be without his key man for Friday's clash in Sao Paulo, with Flamengo's Everton Ribeiro on standby.

Brazil's team doctor Rodrigo Lasmar confirmed a decision will be made on Neymar's availability on Friday and Tite added: "We will have to wait and see.

"If we are without Neymar then it will be Everton in his place."

Brazil are already without goalkeeper Alisson and striker Gabriel Jesus but Tite still has a deep squad to choose from for the double-header with Bolivia and Peru.

Real Madrid midfielder Casemiro will captain the side in the absence of Dani Alves, who is regaining fitness after an injury layoff, while Weverton and Douglas Luiz will also start.

"The captain for tomorrow's game is Casemiro," Tite said. "He is one of the captains, one of the leaders we have.

"We have three great goalkeepers but Weverton has played at a high level.

"Douglas Luiz is another. We want to give him greater freedom to attack from the left side. He needs to be able to supply the man up front."

Brazil will belatedly get their qualifying campaign up and running after the first four rounds of fixtures were called off due to the coronavirus pandemic.

The Selecao won the 2019 Copa America but have advanced past the quarter-final stage of the World Cup just once since 2002, when they won the fifth of their titles.

That occasion was on home soil in 2014, in which they suffered a humiliating 7-1 semi-final defeat to Germany.

"It is about enjoying the pressure," Tite said at his pre-match news conference on Thursday. "It is my responsibility to make decisions and win titles.

"I have the opportunity to be a world champion with Brazil. But this is a team under construction."