UPDATE 9/7, 12:00 p.m. ET: NFL reporter Ian Rapoport reports that the Raiders have released Antonio Brown.

AB's agent, Drew Rosenhaus, tells Adam Schefter that Brown is now a free agent and will put his focus into immediately signing with a new team.

NFL insiders believe that the AB's next stop might be in New England. ProFootballTalk received a text from an unnamed NFL coach claiming he believes Bill Belichick will pursue Brown. 

See original story below. 

Antonio Brown's time as a Raider has taken yet another left. The wide receiver has demanded his release from the team on Instagram.

"I have worked my whole life to prove that the system is blind to see talent like mines," his caption says. "Now that everyone sees it, they want me to conform to that same system that has failed me all those years. 'I’m not mad at anyone. I’m just asking for the freedom to prove them all wrong.' Release me [Raiders]."

ESPN's Adam Schefter said the reason behind Brown's latest demand could be the $215,073.53 fine he got hit with for conduct. With that ruling, the Raiders voided $29.125 million worth of his guaranteed money.

By fining Antonio Brown $215,073.53 last night for conduct detrimental to the team on Sept. 4, the Raiders voided the $29.125 million worth of guaranteed money in his deal, per league sources.

This could help explain why Brown is now asking the Raiders for his release.

— Adam Schefter (@AdamSchefter) September 7, 2019

In addition to fining Antonio Brown $215,073.53 for conduct detrimental to the team that voided $29.125 million worth of guaranteed money in his contract, the Raiders sent Brown a letter that he no longer will be entitled to termination pay if they release him, per sources.

— Adam Schefter (@AdamSchefter) September 7, 2019

ESPN's Jeff Darlington added that he received an email from Brown explaining that the Raiders' fine prompted his decision. There's “no way I play after they took that and made my contract week to week," Brown said.

Last week, rumors started to surface revealing that AB was facing a possible suspension heading into the season following his altercation with general manager Mike Mayock. There were claims that this suspension would be punishment for Brown allegedly threatening to punch him in the face. Brown issued an open apology to his team and the media afterward.

The $1 million signing bonus AB got from the Raiders was split into two $500,000 workout bonus, according to Spotrac. He lost that after missing 85 percent of the team's offseason program. If he's released before Week 1, then he'll have no money to show for his time in Oakland.