Originally Posted by JP
Jason will be in the film so long as Vaughn is still producing. Whether he's Azazel is another story.
Off the top of my head, I could see him as a future (much older) version of Pyro or even a future (much older) version of Gambit.
Or maybe Fabian Cortez, whose ability is to augment the powers of other mutants, and who perhaps uses that to give a boost to Magneto in the future.