A craftsman was assisting with the replacement of a conveyor belt scraper. He handed the new scraper through the access port of the head box to his co-worker & helped position it in place. As he did this he felt a pain in his abdominal region. Although the date of injury was 11/13/12 the employee was diagnosed with a hernia on 12/5/12.Employee is scheduled for surgery on 12/18/12.