 In September 1862 Whipple was assigned to the Third Army Corps, and on December 13–15 participated in the Battle of Fredericksburg.Whipple was severely wounded by a sharpshooter at Chancellorsville on May 4, 1863, received last rites on the battlefield and was taken to Washington.Just before Whipple's death on May 7 President Lincoln, a friend of Whipple's, promoted him to major general of volunteers.