If that was lip-syncing, she's an even better actress than I thought she was. But that was apparently the case, at least according to this passage from a HuffPo report (Minor is pre-game show producer Rickey Minor):
Although entertainers can perform live, Minor insisted that Hudson and Faith Hill, who sang "America the Beautiful" before the national anthem, use the tracks the NFL requires them to submit a week before the game.
But even that explanation's unclear. What "tracks" does this statement refer to? Background tracks? Were some parts lip-synced, some not? Whatever. To quote a HuffPo commenter: "That Lady can flat out SANG!"
Judge for yourself:
This article appears in Jan 28 – Feb 3, 2009.