Fans like to cast a handful of actors for a lot of roles. Nathan FIllion is one. The female version of that is Katee Sackhoff, who fans have been dream casting in lots of roles, especially those of superheroes. The latest rumor: she would be playing Captain Marvel in Avengers: Age of Ultron. Captain Marvel is definitely getting teed up for a Marvel Cinematic Universe appearance, but it won't be Sackhoff in the role.
Talking to Vulture she said:
“As of this moment, I have not sat down with anybody from Marvel for any role specifically. But that doesn’t necessarily mean that something with Marvel is completely off the table for the future.”
That last bit is standard actorspeak for "Yes, I would like to have a job," which is why all the stories with headlines like "So And So Would Be Open To Playing A Superhero" are such bullshit. Most actors are open to most roles, depending on salary and timing.
This latest round of discussion came because Sackhoff tweeted about a secret job she was doing that seemed to involve her getting a rubber supersuit of some sort. She still isn't saying what that job is, but she did say this:
“It's not necessarily a movie and not necessarily a superhero that you would think of."
So it's TV or a webseries. And it's not Marvel. Is it one of the many, many DC shows happening these days? I have no idea. This is the series of tweeted clues she sent. Do you recognize any of this as being a possible DC character? Or is this unrelated to The Flash/Arrow/Gotham completely? Speculate away!
As for Sackhoff in Marvel - I wouldn't hold my breath. I feel like she's too obviously a fan choice to ever actually cross over to being a real choice.