
Tyler Moore celebrates hitting a two-run home run against the Baltimore Orioles with first baseman Adam LaRoche. (Associated Press photo)

Tyler Moore celebrates hitting a two-run home run against the Baltimore Orioles with first baseman Adam LaRoche. (Associated Press photo)

With Washington Nationals right fielder Jayson Werth (28), third baseman Ryan Zimmerman (11) and first baseman Adam LaRoche (25) behind him, manager Davey Johnson (5) checks the lineup, during a baseball game against the New York Mets at Nationals Park Tuesday, June 4, 2013, in Washington. The Nationals won 3-2. (AP Photo/Alex Brandon)

Adam LaRoche and the Nationals celebrate their first walk-off win of the season, beating the Mets on Tuesday 3-2. (Associated Press photo)

Adam LaRoche and the Nationals celebrate their first walk-off win of the season, beating the Mets on Tuesday 3-2. (Associated Press photo)

The Washington Nationals fell to .500 Thursday night after a 2-0 loss to the Baltimore Orioles. Davey Johnson, left, and Adam LaRoche, right, look on during the game. (Associated Press photo)

The Washington Nationals fell to .500 Thursday night after a 2-0 loss to the Baltimore Orioles. Davey Johnson, left, and Adam LaRoche, right, look on during the game. (Associated Press photo)

Nationals' right-hander Nate Karns turned in 4 1/3 strong innings in his major league debut. In the Nationals' 9-3 victory over the Orioles, the rookie's start was backed by Adam LaRoche's third multi-homer game of the season as well as back-to-back shots from Tyler Moore and Roger Bernadina.

Nationals' right-hander Nate Karns turned in 4 1/3 strong innings in his major league debut. In the Nationals' 9-3 victory over the Orioles, the rookie's start was backed by Adam LaRoche's third multi-homer game of the season as well as back-to-back shots from Tyler Moore and Roger Bernadina.