It's being reported that although The Undertaker has been written off of television for the time being after getting attacked by The Shield, he was actually feeling fairly well after his recent matches, more so than he has over the past few years.
In preparation for his match against C.M. Punk at WrestleMania 29, Undertaker reportedly tried some new diet and exercise routines that have helped him feel better. Also, while he wanted to have a good performance with Punk, he tried not to push himself too hard like he has at the past number of WrestleMania events in his grueling matches against Triple H and Shawn Michaels.
As of right now there's still no timetable set for The Undertaker's return, although it was previously reported that he might come back at or around SummerSlam to get revenge on The Shield.