Mark Ruffalo is uncertain about the Hulk's role in future Marvel movies.

The 47-year-old actor, who starred as Bruce Banner/The Hulk in 'The Avengers' and is set to reprise the role in 'Avengers: Age of Ultron', has revealed the character's participation in other planned projects remains unclear.

Asked how many films he has left to complete on his Marvel contract, Mark said: ''I think it's four [films left] now, but that could always go further. That could include different--I could show up in another character's movie; I could do Avengers 3 and 4; I could do a Hulk standalone; I could do a combination of those things. That's four or five, I think.''

''I don't know if I'm in [Captain America: Civil War] yet. I don't know. Sometimes these things happen at the last minute in this world. I really don't know where I fit in from here on out, and I'm not sure they do.''

He said, too, that an ongoing rights issue between Marvel and Universal means a standalone Hulk movie remains unlikely for the time being.

He told Collider: ''As far as a Hulk movie, a standalone Hulk movie, Marvel doesn't really have the rights to that yet. That's still Universal's property, so there's that issue.

''That's a big impediment to moving forward with that. Now I don't think that's insurmountable, by the way, but I don't know where it's going from here for me.''