No Undertaker at No Mercy??

okk i am still surprised that taker didnt show up at no mercy at all. i mean how does vince mcmahon leave out one of the greatest wrestlers of all time on a ppv?? even tho alot of ppl were waiting y2j to show up (we knew he wasnt going to) i was kinda disappointed not see taker as he would have definitely made an impact and possible make no mercy better than it was. any thoughts or opinions on why he wasnt there??