Now this information is pretty obvious if anyone has read Civil War or The Death of Captain America. In which Crossbones and The Winter Soldier play a pretty large role after the events of Civil War. Now Justin Kroll of Variety has revealed alongside Daniel Bruhl's unknown villain; Frank Grillo's character Brock Rumlow will indeed embrace his inner demons and become Crossbones
Beat by Marvel in that one, two things he will play villain but not main one, Crossbones still main
— Justin Kroll (@krolljvar) November 14, 2014