OK, it's not going away immediately, a la Smith or Kidnapped, but after the next two episodes, Traveler is gone for good, and this news comes from the creator himself.
Creator/producer Dave DiGilio has been keeping a blog over at TVGuide.com, and he reveals that the network has let the contracts of the actors on the show lapse and that the next two episodes of the show (the show returns July 11) mark the end of the series. And while it's not the final final decision on the show, when the creator of a show says it's true, that's definitely a sign. Though it's not like they didn't see it coming, after the show was put in as a summer replacement, the episodes cut, etc.
He also gives some cool behind-the-scenes scoop of epsiode "The Reunion."