Undertaker suffered a broken orbital bone, a broken nose and a concussion in his match last Tuesday against Rey Mysterio, which aired on Friday's episode of SmackDown!.
It is believed 'Taker suffered the injury while taking the seated senton move by Mysterio during the match.
He has been recommended to take time off due to the injury, which would take him past the Fatal 4-Way event. It's being said that it's a 50/50 chance as to whether he would be able to wrestle on the show.
Due to the lack of depth on the SmackDown! brand, Rey Mysterio has been called back to action to fill Undertaker's scheduled position on live events and television. He was set to take time off from the road for a scheduled vacation. No decision has been made regarding the World Heavyweight Championship bout at Fatal 4-Way, but logic would have Mysterio as the replacement if Undertaker can't wrestle.