Regarding Sting not signing a deal with WWE yet, it’s more because WWE is dragging their feet. We noted before that WWE officials are in no hurry to get Sting signed for a WrestleMania XXX match but word is that Sting himself was hoping for a match against The Undertaker at this year’s event.
Since Sting lives in the Dallas area, he is willing to meet up with The Undertaker and work out the match in private at Undertaker’s gym, over and over, to get it right, which is what Undertaker’s opponents have done for the past several years. That’s one of the reasons the matches have gone over so well. There was some concern that Brock Lesnar, who is in it because he makes big money for a limited amount of work and only has a certain number of dates on his contract, may not be willing to spend several extra days working with Taker to get the entire match worked out.
Source: Wrestling Observer Newsletter