The embattled wide receiver was seen exiting his private jet Saturday as he touched down in Miami -- where he owns a home. As he walked the runway, AB had an incredibly pained look on his face ... which is understandable after everything that's happened.

BTW, he was wearing Supreme gear here up top -- not Nike, which just dropped him this past week amid the mounting allegations. He also carried a Louis Vuitton briefcase.

While he looked pretty down in the dumps when he got back to Miami, AB was trying to put on a brave paid face before leaving the airport in New England ... posting a photo of himself sitting on top of a Rolls-Royce with the caption, "The Journey #Iknowimspecial #Whytheyplaying." Looks like he snuck in some Nike after all in his footwear.

As we reported ... Antonio was released by the Patriots Friday after a whirlwind of bad news for him, including a lawsuit alleging rape and sexual assault ... a Sports Illustrated story detailing more alleged sexual and behavioral misconduct ... as well as a reported attempt to contact one of his accusers with menacing texts.

Despite one good outing, it looks like the Pats had seen enough ... cutting him loose before Sunday's game against the Jets. AB's an unrestricted free agent now, and the NFL is still investigating the claims against him, not having come to a conclusion yet.