User blog comment:ADour/New CAPTAIN AMERICA: THE WINTER SOLDIER posters!/@comment-2031194-20140207064606/@comment-1895174-20140207191826

We've seen him in each of the films' trailers (he's one of the people Cap knocks out in the elevator), but I can't blame you for not recognizing him since he's unmasked. It appears the character won't be called "Crossbones" at all in the movie, instead just being referred to as "Agent Rumlow".

Here's a picture of Frank Grillo as Brock Rumlow -

For what it's worth, the major character we've seen the least of is Georges St-Pierre's Batroc. To my knowledge, there's only one image out there of him, and it was released less than a week ago -