User blog comment:Thejoker2508/Grimmjaw: Dead or Alive/@comment-1194223-20111127174734

I'm not going to claim anything conclusive, since the bleach wiki mods will jump on me like always. I'll just say that, after Kubo's interview at Jump Festa, we are left to assume that Grimmjow died, or will never appear again. Kubo was speaking of him in past tense.

Also, Harribel survived the war (Healed by Orihime). I guess that gives even more probability to Grimmjow's death, since Hueco Mundo already has a new ruler, who is a VL by the way.