So who is this character exactly? Crossbones (aka Brock Rumlow), usually appeared in the comics as a henchman to the Red Skull (played by in the first film by Hugo Weaving, who has no desire to reprise the role again unless he's contractually strongarmed into doing so). He also has a significant role in the "Civil War" storyline that also includes Falcon (being played by Anthony Mackie) and Winter Solider, so this could be exactly where Marvel is drawing their story.
More to come we're sure. The Russo Brothers direct the picture that will hit theaters on April 4, 2014. [Variety]