io9 has some casting pages from episode #4.14, while EW.com's Michael Ausiello has spoilers for a February episode.
In another spoiler on the November 18 column, Ausiello commented that "I hear The CW will likely take the don't-fix-if-not-broke approach and keep its Thursday line-up intact next season." Yet "In related news, there was a wild rumor going around last week that Supernatural received a green light for a fifth season. The network quickly squashed it, but, man, for about 30 minutes last Monday I thought Christmas had come early for all you Supe Nazis."