The official Japanese Pokemon website has posted a teaser for an "important announcement" next Tuesday, January 8. No further information is available.
The most recent core Pokemon games were Pokemon Black and White 2, which released in North America in October 2012 behind positive critical plaudits.
Both games cracked the NPD Group's top ten United States sales chart during their debut month, but neither charted in November (a month filled with heavyweights like Call of Duty: Black Ops II and Halo 4).
Most recently, the Pokemon Company released an official Pokedex iOS app. Similar to its in-game counterpart, the $2 Pokemon Pokedex iOS app provides a range of data, including information regarding how to evolve certain Pokemon, locations where specific creatures are found, and which types of attacks Pokemon are susceptible to.