The Undertaker was “hurting real bad” during the Royal Rumble match due to an injured and previously surgically repaired hip, according to Dave Meltzer of Wrestling Observer Radio. He was also in lots of pain backstage.
WWE structured the Rumble match where Undertaker didn’t have to do much, but it’s obviously concerning for WrestleMania, since he will be working a full match (rumored to be against Roman Reigns).