From Bulbanews, your community Pokémon newspaper.
Unknown if Pokémon related
Update: The mysterious silhouette was not Pokémon related and it is a silhouette of Soriti Horse which is a new 3DS eShop title combining Solitaire and horsing racing. It will release in the Japanese Nintendo eShop on July 31 and cost 500 yen.
The official Game Freak website recently unveiled a silhouette with a "Coming Soon" notice under it. The image was also accompanied with a caption reading "That well-known game played all over the world will be reborn with a new shocking collaboration!".
It is currently unknown if the silhouette is Pokémon related or not.