Simon Cowell will not be able to appear on Tuesday and Wednesday's episodes of "America's Got Talent".<br />Cowell suffered a serious back injury on Sunday when he fell off an electric bike.<br />The reality TV star judge broke his back in several places.<br />Daytime Emmy winner Kelly Clarkson will be sitting in for him.<br />According to NBC, Clarkson will join fellow judges Howie Mandel, Heidi Klum, and Sofia Vergara.
