Apparently, they are still working out the 3D kinks.
http://screenrant.com/green-lantern-trailer-2-thor-sandy-108258/
Because this is Warner Bros. we are talking about, I'm concerned. They're the ones who rushed Clash Of The Titans into a 3D conversion last spring, which drew a firestorm of criticism from the public and other studio heads for making their film look like crap and tarnishing the 3D brand. Then, barely six weeks before opening, they pulled the plug on their 3D conversion of Harry Potter And The Deathly Hollows part I and put it out in 2D, saying they couldn't finish it in time for release.
They couldn't possibly back out again on Green Lantern, could they? Just 2 1/2 months before release... 😗