Police and the Brazil Football Association (CBF) have said they will investigate allegations that Flamengo midfielder Gerson was subjected to racist abuse by a rival player during his team's 4-3 win over Bahia on Sunday.
Law enforcement "will hear the player and the others involved will be called to testify in an attempt to clarify the facts," Rio's Civilian Police said in a statement.
Gerson alleged that Bahia's Colombian midfielder Juan Pablo Ramirez made a racist remark during the league encounter at the Maracana stadium.
"I would like to say that I have played many games as a professional and I've never said anything [before] because I had never suffered prejudice," Gerson said.
"But after conceding one of the goals, Ramirez started arguing with [Flamengo's] Bruno Henrique and I went to talk to him and he told me: 'Shut your mouth, Black.' He has to learn to respect people."
Ramirez denied the allegation, according to his club, but has been removed from the team until the investigation is completed.
The club said in a statement: "The athlete [Juan Pablo] 'Indio' Ramírez vehemently denies the accusation and he is being given the opportunity to defend himself against something so serious.
"The club understands, however, that it is indispensable, essential and fundamental that the victim's voice is predominant in cases of this nature. Thus, it has decided to immediately remove the player from the team's activities until the conclusion of the investigation."
Bahia president Guilherme Bellintani called Gerson to show solidarity.
In a statement, the CBF said it has requested its sporting disciplinary tribunal to open "an immediate investigation" after Gerson reported the alleged incident in the official game report adding: "we reiterate our profound rejection of racism."
Flamengo tweeted a message supporting Gerson: "Sunday night was a joy for the victory, but a revolt for the sad episode. And no one is going to shut you up. Neither today or ever! The nation is with you."
Meanwhile Neymar shared Gerson's Instagram post adding: "Say no to racism. For how long?"