Salvatore Licitra, who took a nasty spill Tuesday night on the way to a promo event for his new CD, will sing go on and Canio tonight at the Met. The tenor reportedly tore a couple of tendons in his shoulder and will have to wear a sling during Pagliacci. Some of the staging will be altered to accomodate his injury. Fortunately, Licitra’s onstage partner is the cool-headed Patricia Racette, who can be counted on to remember not to grab the arm as the action heats up.