Brazil have confirmed Fagner will start in place of Danilo for their World Cup clash with Costa Rica, the Manchester City defender having been ruled out through injury.
The Brazilian Football Confederation (CBF) said in a brief statement Danilo had complained of pain around his hip during Thursday's training session.
Danilo has now been diagnosed by Brazil's team doctor Rodrigo Lasmar with a "muscle injury in the right hip region" and he will miss Friday's Group E game.
Brazil are already without their regular right-back Dani Alves, the Paris Saint-Germain star missing the tournament due to a knee injury.
The CBF confirmed Tite will name Fagner in his starting XI to face Costa Rica, Brazil having opened their Russia 2018 campaign with a 1-1 draw against Switzerland.
"Danilo will begin treatment with the physiotherapists and will continue under the observation of the medical department," the CBF said.
It will be the only change after Neymar was passed fit despite appearing to be troubled by an ankle injury during training this week.
Corinthians defender Fagner, who made his international debut in 2017, will win his fifth Brazil cap against Costa Rica.