"Update: Well to hold you over.. we just remembered in two different brochures given to us at the Midway booth, that it confirms Raiden is in the character roster of MK: Deception. Also, we read earlier today that Gamespot has confirmed that Jax is also in the line-up."

So far this is the closest we have to a confirmation of the thunder god's return to MK:D. You can find it in the news archives of this site for the month of May. There was also a supposed mention of it on the X-Play site, but they took it down. So there is a good chance he will return, but its not really 100% certain yet since there is no other confirmation or images yet. I recommend keeping an eye on the Confirmed Character List thread's first post, since that person is keeping acurate track of who is confirmed and rumored to be in the game.