When Marvel announced its Phase 3 slate last October, an obvious omission from the list was a solo vehicle for Mark Ruffalo's Hulk.

The man who plays Bruce Banner cleared up why fans won't be seeing a Hulk film from Marvel any time soon at Monday night's world premiere of "Avengers: Age of Ultron."

"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," Ruffalo told Badass Digest. "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."

Universal Studios produced the last solo Hulk film in 2008 with Edward Norton playing the big green giant. Ruffalo took over the part in 2012's "The Avengers," joining forces with Iron Man (Robert Downey Jr.), Captain American (Chris Evans), Thor (Chris Hemsworth), Black Widow (Scarlett Johansson) and Hawkeye (Jeremy Renner).

"The Incredible Hulk," starring Norton, featured Downey's Tony Stark in the post-credits scene and the events of the movie exist in the greater Marvel Cinematic Universe.

Ruffalo isn't sure when his Hulk will return to the screen. There were rumors of him joining the "Guardians of the Galaxy," but those now seem unlikely given the movie's success without any "Avengers" crossover.

"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," the 47-year-old actor said.

Ruffalo's Bruce Banner also made a brief cameo in the post-credits scene of "Iron Man 3" in 2013.

"Avengers: Age of Ultron" premieres in theaters on May 1.