While the truth is that all anyone really wants Sam Worthington to do is make James Cameron's planned Avatar sequels, he's become a pretty big star in his own right, and has to find something to fill his time until Cameron gets his ass in gear. Deadline reports that Worthington is now attached to star in an untitled sci-fi project, which Warner Bros. recently acquired from screenwriter Aaron Guzikowski.
Little is known about the story of this new adventure, except that it is about a war in outer space (presumably not between big blue tree-huggers and evil humans though), and it sounds as if the idea is to try and keep it 'grounded', so more grit than flash in this one.
Guzikowski is fairly new on the Hollywood scene, having gained attention for writing Contraband, about a security guard who returns to smuggling to get out of financial difficulty, which will star Mark Wahlberg and is set for a March 2012 release. He also wrote Prisoners, which should start shooting this autumn, and is working on a couple things for TV.
It'll be a while before this new film goes in front of the cameras though, as no director is attached, and Worthington is a busy boy, so there's no way to when when he'll be able to fit it into his schedule.