Taker on Smackdown?

Maybe I’m grasping at straws here, but what are the chances that Undertaker appears on Smackdown to answer Cena’s challenge? After all, Cena is a free agent so he can very well appear and Smackdown WAS the Undertaker’s show for years.

Thanks!

Brian

You'd think they'd advertise that sort of thing in advance, but really nothing about this bizarre buildup surprises me at this point.