"We appreciate the hard work of many people over the past 11 days, but we feel that it is best to move in a different direction at this time," the team said in a statement.
Text messages sent by Brown to a woman alleging sexual misconduct were viewed by some in the organization to have crossed the line, a source told ESPN. The text messages -- which were reported by Sports Illustrated on Thursday and included a picture of the woman's children, which her lawyers called intimidating -- were significant in that they were sent while Brown was a member of the Patriots, the source said.
Up to that point, the issues surrounding Brown were all from before he had signed with the team on Sept. 9.
Brown, who had practiced with the Patriots earlier Friday, tweeted his thanks to the organization shortly before the move was announced.
Brown has been accused of sexually assaulting his former trainer, Britney Taylor, according to a civil lawsuit she filed Sept. 10. A source previously told ESPN's Jeff Darlington that Brown declined to sign a $2 million-plus agreement with Taylor in a proposed settlement.
Taylor met with the NFL on Monday. A source had told ESPN that there are "more interviews and information-gathering being conducted now beyond Taylor." It remains unclear when or if Brown will interview with the league.
With his release, Brown becomes an unrestricted free agent eligible to sign with any team. The NFL released a statement Friday night that said Brown would not be placed on the commissioner's exempt list while he is a free agent but warned, "If he is signed by a club, such placement may become appropriate at any time depending on the status of the investigation."
The NFL also said its investigation into Brown is "ongoing and will be pursued vigorously and expeditiously."
In addition to the lawsuit, Brown faces the allegation of sexual misconduct by a female artist who was working at his western Pennsylvania home in 2017. That allegation was part of a Sports Illustrated report published Monday that detailed domestic incidents involving Brown, a charity auction theft and multiple unpaid debts.
On Thursday, the lawyer for the artist reached out to the NFL after Brown apparently sent what were described as threatening text messages to her client. The sides spoke Friday morning, with the woman's attorneys saying in a statement that the league "pledged to conduct a thorough investigation under its Personal Conduct Policy." According to that statement, the league also contacted the Patriots, who then directed Brown to have no further contact with the woman.
"The NFL and the Patriots clearly took our client's concerns seriously," lawyers Lisa Banks and Debra Katz of Katz, Marshall and Banks said in a statement Friday. "She wanted the threats and intimidation to stop and we hope that will be the case. The NFL has assured us that regardless of Antonio Brown's roster status, it will continue to investigate all claims regarding his behavior.
"We are gratified that the NFL recognized that it has an important role to play in policing player conduct that is sexually harassing and threatening."
Brown, 31, made his debut with the Patriots on Sunday against the Miami Dolphins, totaling four catches for 56 yards and one touchdown.
Clark: Pats reached a breaking point with AB
Ryan Clark says he isn't surprised by Antonio Brown's release from the Patriots as they aim to maintain chemistry within the locker room.
On Thursday, Brown answered four questions from reporters, marking the first time he had addressed the media since joining the Patriots. He was not directly asked about the civil lawsuit or the allegations of sexual misconduct.
"I'm just here to focus on ball," Brown said in an interview that lasted just one minute, when asked if he had heard from the NFL about his availability.
The Patriots had agreed to pay Brown a $9 million signing bonus, which was divided into two parts: $5 million that was due to be paid Monday and $4 million that was due Jan. 15.
Brown, however, is unlikely to get any of the bonus because of a representation warranty clause that calls for a player to disclose any situations that might prevent continued availability, a source with knowledge of the situation told ESPN's Jeremy Fowler.
The NFL Players Association could file a grievance over the money, and sources told ESPN last week that Brown was under a confidentiality agreement while attorneys for he and Taylor discussed a potential settlement for months. But the team can argue Brown could have notified it of any looming issues, even in generalities.
Brown, instead, likely will be paid by the Patriots for only Weeks 2 and 3.
"It's unfortunate things didn't work out with the Patriots," the receiver's agent, Drew Rosenhaus, said. "But Antonio is healthy and is looking forward to his next opportunity in the NFL. He wants to play the game he loves, and he hopes to play for another team soon."
New England is 2-0 this season, winning those games by a combined 76-3. The defending Super Bowl champions host the New York Jets on Sunday. According to Caesars Sportsbook, New England's odds to win that game went from -22.5 to -21.5 after Brown was released. The over/under went from 44 to 43.5, per Caesars.
Without Brown, the Patriots have Julian Edelman, Josh Gordon, Phillip Dorsett and undrafted Jakobi Meyers and Gunner Olszewski on the wide receiver depth chart, with special-teams captain Matthew Slater a niche/emergency option.
In other moves Friday, the Patriots signed linebacker Scooby Wright to the practice squad and released defensive lineman Gerri Green from the practice squad.