Washington Nationals' Jordan Zimmermann delivers a pitch against the Houston Astros in the first inning of a baseball game Thursday, Aug. 9, 2012, in Houston. (AP Photo/Pat Sullivan)

Houston Astros pitcher Lucas Harrell lies on the mound after dropping to avoid a line drive ball from Washington Nationals' Roger Bernadina in the first inning of a baseball game, Thursday, Aug. 9, 2012, in Houston. Bernadina singled on the play. (AP Photo/Pat Sullivan)

Houston Astros first baseman Scott Moore reaches for the ball and the out on Washington Nationals' Jayson Werth (28) in the second inning of a baseball game, Thursday, Aug. 9, 2012, in Houston. (AP Photo/Pat Sullivan)

Houston Astros' Lucas Harrell delivers a pitch against the Washington Nationals in the first inning of a baseball game, Thursday, Aug. 9, 2012, in Houston. (AP Photo/Pat Sullivan)

Washington Nationals pitcher Jordan Zimmermann wipes off the sweat after hitting Houston Astros' Scott Moore with a pitch in the second inning of a baseball game, Thursday, Aug. 9, 2012, in Houston. (AP Photo/Pat Sullivan)

Washington Nationals' Roger Bernadina (2) steals second base as Houston Astros' Jose Altuve, left, loses the ball in the fourth inning of a baseball game, Thursday, Aug. 9, 2012, in Houston. Bernadina went on to score on a Adam LaRoche single. (AP Photo/Pat Sullivan)

Washington Nationals' Michael Morse (38) passes Houston Astros first baseman Scott Moore (46) on his way around the bases on a solo homer in the sixth inning of a baseball game, Thursday, Aug. 9, 2012, in Houston. (AP Photo/Pat Sullivan)

Washington Nationals' Michael Morse, right, is congratulated by bench coach Randy Knorr after hitting a solo home run against the Houston Astros in the sixth inning of a baseball game, Thursday, Aug. 9, 2012, in Houston. (AP Photo/Pat Sullivan)

Washington Nationals' Drew Storen (22) and Kurt Suzuki (24) celebrate their 5-0 win over the Houston Astros to sweep the four-game baseball series, Thursday, Aug. 9, 2012, in Houston. (AP Photo/Pat Sullivan)

FILE - In this Aug. 9, 2012, file photo, Washington Nationals' Sean Burnett throws a pitch during a baseball game against the Houston Astros in Houston. The Los Angeles Angels added two more new arms to their retooled pitching staff on Wednesday, Dec. 5, by agreeing to an $8 million, two-year deal with Burnett and a $15 million, two-year contract with right-hander Joe Blanton. (AP Photo/Pat Sullivan, File)