Adriano in nightclub tirade
The video appeared just hours after the club's director of football, Zinho, confirmed the former Inter Milan man would not be back at training until after the weekend.
The former Brazil international, who is recovering from ankle surgery and is yet to make an appearance since rejoining the club earlier this year, has already breached an agreement with the club that he would miss no more than three training sessions.
"I'm just here to represent," he told the crowd on Thursday night. "Everyone knows that I always loved Flamengo, and that's something that no one will ever take away from me.
"I'm from the slums," he said. "You can all say what you want. Born and raised at Vila Cruzeiro. You got that?
The striker, who appeared 48 times for his country, then concluded by suggesting his words would later appear in the media.
"I just want to say that I love my people, I love Flamengo. And here I am. If something comes out on the press (on Friday), you know what happened. I know that this is going to be on the internet tomorrow. I'm from the slums. Thanks, love you."
The 30-year-old, who is a long way off match fitness, is set to meet with club officials when he returns to training on Tuesday morning.