Texas A&M athletic director Bill Byrne, who oversaw the school's upcoming departure from the Big 12 and everything from national championships to the end of the storied football rivalry with Texas, is retiring. Byrne will discuss his decision at a Tuesday afternoon news conference in College Station, according to a school official with knowledge of the decision. The school said only that Byrne would make an announcement "regarding his future" and the person spoke to The Associated Press late Monday on condition of anonymity because details had not been released.