Feb 7 (Reuters) - Gregg Williams, who was banned indefinitely for orchestrating the New Orleans Saints' bounty scandal, has been reinstated by the NFL and hired as a defensive coach with the Tennessee Titans, the team said on Thursday. Williams, who was hired by the St. Louis Rams before the 2012 NFL season but missed it due to the ban and was subsequently fired, will be introduced as the Titans senior assistant/defense at a news conference later on Thursday.