While many observers of the Yankees are citing concerns about center field and who will be their fifth starter, Brian Cashman is more concerned about the health of Mariano Rivera and Jorge Posada. ?Our catcher and closer are coming off shoulder surgeries,? Cashman said. ?That?s what concerns me, and that?s what people should be focused on. Everything is coming along fine, but nobody usually has hiccups this early. Posada?s just throwing at 90 feet on flat ground, and Mo?s not even throwing yet.?