With her eye on the Olympics, Serena Williams is joining the United States for a Fed Cup playoff against Ukraine at Kharkiv, Ukraine. The best-of-5 series on clay begins today and Williams faces 17-year-old Elina Svitolina in the second singles match. Williams, a 13-time Grand Slam champion, needs to play twice in the Fed Cup in 2012 to be considered by the U.S. Tennis Association for the Olympic team. This U.S. team, captained by Mary Joe Fernandez, also features Christina McHale, Sloane Stephens and Liezel Huber. The country that wins will be promoted to the main Fed Cup group in 2013 and be able to compete for the title. The loser will drop to World Group II.