Mariano Rivera has been relieved. The Hall of Fame closer for the New York Yankees no longer is serving as a co-chair of the President’s Council on Sports, Fitness & Nutrition, though he remains a member of the council, the U.S. Department of Health and Human Services confirmed. The two other co-chairs — former NFL running back Herschel Walker, who is running for U.S. Senate in Georgia, and beach volleyball player Misty May-Treanor, also reappointed by former President Donald Trump in December 2020 on his way out of office — no longer sit on the council. Trump first announced the three athlete…