Andy Roddick watches the ball during his match with Argentina's Juan Martin Del Potro in the fourth round of play at the 2012 US Open tennis tournament,  Wednesday, Sept. 5, 2012, in New York. (AP Photo/Charles Krupa)

Photo by: Charles Krupa

Andy Roddick watches the ball during his match with Argentina's Juan Martin Del Potro in the fourth round of play at the 2012 US Open tennis tournament, Wednesday, Sept. 5, 2012, in New York. (AP Photo/Charles Krupa)