It's already been confirmed Dr. Henry Wu (played by B.D. Wong) will have a significant role in Jurassic World as he steps out of Hammond's shadow, but the original stars, played by Jeff Goldblum, Sam Neill, and Laura Dern, have all been written out, apparently. However, multiple reports have indicated that they might still play some sort of role in Jurassic World, even if they don't make physical appearances. For example, the Jurassic World Twitter account recently sent out an image of a book written by Ian Malcolm titled God Creates Dinosaurs. If that makes it into the movie, it'd be a neat little easter egg/cameo.
