"Antonio Brown is not a Nike athlete," a Nike spokesman confirmed in a statement to AFP after the Boston Globe newspaper first reported the move.
Nike has declined to elaborate on why the move was made or the timing of the decision to drop the NFL standout, who was released by the Oakland Raiders on September 7 and quickly joined the reigning Super Bowl champion Patriots.
Three days later, Brown's former trainer, Britney Taylor, filed a civil lawsuit in US District Court in Miami accusing Brown of two incidents of sexual assault in June 2017 and rape during a May 2018 incident in Brown's Miami home.
Brown himself spoke to reporters on Thursday for the first time since Taylor sued, but he side-stepped questions about the matter and whether he expects to face any punishment by the league.
"I appreciate that question," Brown said when asked about his standing with the league. "I'm just here to focus on ball and look forward to getting out there in the home stadium, being with the team."
The NFL has launched its own investigation into the allegations against Brown for possible violations of league policy.
The league can take action regardless of the outcome of Taylor's lawsuit.
Just days after the lawsuit was filed, Brown was dropped by American football helmet manufacturer Xenith.
Brown announced earlier this month he was wearing a Xenith helmet this season after losing two appeals to the NFL to wear a helmet brand no longer certified by the league.
Taylor's lawsuit describes Brown's personal life as "apparent chaos" in part because of his numerous endorsement deals, saying he arrived late to events he was required to attend for numerous sponsors, including Nike.
A Nike shoe bearing Brown's name and a catchphrase he popularized, "Business is Boomin," no longer appears on Nike's website.
Brown indicated he was focusing on football and making the most of his opportunity with a Patriots team led by no-nonsense coach Bill Belichick and superstar quarterback Tom Brady.
"Well, it's football," Brown said. "I'm grateful to play football every time you walk in the door here, you know, be your best for the team. Every time I walk in here, I just want to make sure I'm preparing to give these guys my best."