Where was HBK at Wrestlemania 30?

I am big Shawn Michaels fan. HBK is known as Mr. Wrestlemania. But, he did not appear on tv at one of the biggest Wrestlemanias. This year's Wrestlemania celebrated 30 years. I find it weird that he didn't want to be on it or WWE didn't want to have him cut a quick promo. Heck, I thought it would be cool to see him come out with Austin, Rock, and Hogan. Maybe he just wanted to skip a Wrestlemania. But I think he should have atleast been involved in a little skit.