It's optimistic and probably wrong but I'm thinking they're holding back on telling us who it is because it may be At the Gates. They were talking about getting back together and doing more shows and The Haunted (the At the Gates bassist and one guitarist are members) are playing Ozzfest. I don't know what Nightrage's obligations are though, Lindberg may not be free.
Like I said, I doubt it, but a man can hope.