WWE has ads out that spoil the return date for The Undertaker. Taker will be returning to Raw on February 24th which is the same day of the WWE Network launch and the day after Elimination Chamber.
Undertaker was last seen on Smackdown in April of last year when he was attacked by The Shield. This will be the kickoff of his planned program with Brock Lesnar. As we noted though, plans can still change but as of now that is still the plan for WrestleMania between those two.
