Jeremy Renner's Hawkeye character is finally going to be explored a little more in Avengers: Age of Ultron, and now it sounds like there's a chance that he'll also be included in the storyline for Captain America 3.
In a recent interview with Collider, Renner told the site that he might have a role in Captain America 3. While talking about some of his upcoming projects that actor said:
"There are rumblings of Captain America 3. I don’t know what’s going to happen there. I’ve got to find the time, man (laughs). I’m trying to stay home and I can’t."
Black Widow played a huge role in Captain America: The Winter Solider as did The Falcon, so it's not hard to believe that they would find a place for Haweye in the sequel. He was actually supposed to be in The Winter Soldier but was written out of it in the process with Black Widow taking on some of the things Hawkeye would have been involved with.
I think it would be really cool to see Hawkeye working with Cap and Falcon as they try to find Bucky. Hawkeye and Cap have always had a fun relationship in the comics, and I'd like to see that explored on the big screen.