Is it still possible for Sidney Crosby to come back at all this season or what?

Since going down with a concussion/s (1/ and/or 5/11) and post concussion syndrome (1/6/11). At the same time hes not the only Penguin whom is dealing with all of this as well. The question also applies to other hockey players and other players in other sports as well. The questioner isn't even a fan of his or Penguins as well. But just been following all of the him because of his concussion/s and post concussion syndrome.