Secretary of Defense Lloyd Austin will undergo a medical procedure on Friday, the Department of Defense announced, following previous medical issues that he did not initially disclose to the White House or the American public. Austin will go to the Walter Reed National Military Medical Center on Friday for a “scheduled, elective, and minimally invasive follow-up non-surgical procedure related to his previously reported bladder issue,” Pentagon spokesman Pat Ryder said on Friday. Austin will be unable to fulfill his duties during this time, so Deputy Defense Secretary Kathleen Hicks will assume…