Search results for query: *

The previews for the next episode show Greninja in the episode, albeit appearing in his normal form.

I would not discount Greninja appearing in the SM animé, or Zygarge for that matter. Zygarde plays a role in the games, and I would not be surprised if the power of Zygarde, and possibly Ash-Greninja, is needed to deal with the Ultra Beasts, or whatever other big threats may appear, in the animé.