I wonder how they would do it if it actually came to be. They probably have to have a stage set up before the game and just hope that the Yankees have a save situation to bring him in.
People wonder how it would be for a band to play a song live during an event. Look no further than to wrestling where it has been done before. I give you Triple H coming out to his own theme song performed by Motorhead.
If Rivera came out to a live performance by Metallica, imagine the intimidation factor. I for one am for it.