Following his introduction in Captain America: The Winter Soldier, fans were disappointed to see Frank Grillo's Brock Rumlow killed off in the opening few minutes of Captain America: Civil War. He had only just adopted his Crossbones persona and to say it seemed like a waste of the villain would be an understatement.
However, after teasing a return to the Marvel Cinematic Universe for quite some time now, Grillo has finally confirmed that he's once again suiting up as Crossbones for a "flashback" sequence in Avengers 4 (bear in mind that most cast members weren't given full versions of the script so what he believes is a flashback could just as easily be time-travel as we've suspected for a while now).
"[Crossbones] makes an appearance in the next Avengers movie," he confirmed. "But it's a flashback. Yeah and I'm allowed to say whatever I want because I'm never doing another Marvel movie." I'm sure Marvel Studios won't be happy with that but the question is, where will we end up seeing the villain return?
Are we going back to the moment of his death that led to the superhero Civil War or when he was an Agent of S.H.I.E.L.D.? That remains to be seen but it's fair to say that we need to see something official from Avengers 4 sooner rather than later.