It looks like that Sonic may be receiving the new gen treatment and coming to the PS4, Xbox One and Wii U, at least according to a sign that was apparently on show at the Nuremberg Toy Fair which is taking place until the February 3rd. Now this is as of yet unverified so take it with a pinch of salt, but considering Sonic has been making appearances for over twenty years across generations it isn’t unlikely.
What kind of Sonic game could announced varies from a new Sonic Racing, a potential follow up or a game similar to Sonic Generations. It could even be Sonic 4 Episode III, though that would be a surprise as it depended on the sales of Episode II.
Source: All Games Beta