Matt Hardy apparently has a lot of heat on him in the locker room right now stemming from an incident at Survivor Series. In the final moments of the PPV, when Undertaker was supposed to destroy the locker room, the original plans called for Hardy to receive a Chokeslam from Taker. Hardy told the agent giving him the news that this would slow down the momentum he was starting to gain in WWE. Being the current locker room leader, this naturally got back to Undertaker.
In Cincinnati, Undertaker saw a replay of the Raw versus SmackDown! match and after asking for a rewind, he found that when he came into the ring, Hardy quickly rolled out of the ring and Undertaker began to talk down to Matt Hardy, most notably calling him a mark for rolling out. Talks came up about making an angle out of this, but Undertaker said candidly that he wouldn’t work with Hardy. He then told Hardy to see it from his point of view and asked Hardy what kind of message he was sending to the locker room. Taker finally asked Hardy, “Are you better than everybody else?” Apparently, Hardy had his head down the whole time and just took it.
This may be the reason why Hardy was buried against Randy Orton a few weeks later as Orton never acknowledged the match in his promo before hand and the two also had eight minutes cut from the match. Seeing as how JBL is also somewhat of a locker room leader backstage (or so he sees himself as), the match at Armageddon could just be more punishment in store for Hardy.
Many are actually surprised at this by Hardy considering Hardy has always been one of those guys to do what is asked of him as he respects the chain of command, something he went through in detail in his autobiography with Jeff Hardy. It should also be noted that Hardy has always thought highly of JBL and Taker in the past (again mentioned in his book) so this situation may just be worse on Matt Hardy.