WWE.com is currently advertising both The Undertaker and Shawn Michaels for the upcoming Monday Night RAW taping on January 9 in New Orleans.
Both are expected to be making the appearance to build something involving the upcoming Royal Rumble PPV on January 29 from San Antonio at the Alamodome.
Undertaker last appeared on WWE television back in November on the 900th episode of Smackdown Live indicating he was back and not just a WrestleMania attraction.