Just because he's advertised for the tour doesn't necessarily mean that he'll be back on TV. A few years back I see to remember him doing an overseas tour, after WM I think, but he didn't actually return to TV until sometime after that.
That said, the Undertaker wasn't in a 'vegetative state' at the time. They'd have to come up with some explanation as to why he's back so I guess he would have to go back on TV for that.
Assuming of course that Undertaker actually goes on tour. They could just be using his name to sell more tickets.
