Source: The Wrestling Observer
At this time, The Undertaker's physical health is becoming a concern for WWE officials. 'Taker badly damaged the replaced hip he got several years ago during his WrestleMania 28 match with Triple H. The Undertaker was flying to New York to meet with doctors but now WWE has been paying to fly the doctors to The Undertaker's house in Texas because it's becoming such a frequent process.
The talk as of now is that Undertaker may work the Royal Rumble, make his entrance, do a few spots and then get eliminated.
As far as working WrestleMania goes, it is being left up to Undertaker as we've been reporting. It is also being said that if he does work WrestleMania, it will not be an intense of physical match like he has had the last few years.