Washington left-hander John Lannan allowed three hits in four scoreless innings, and the Nationals lost to the Atlanta Braves 3-2 in 10 innings Wednesday.
Lannan, who struck out two and walked one, would become Washington's No. 5 starter if right-hander Chien-Ming Wang doesn't recover from a strained left hamstring in time to take his first turn.
Braves starter Tommy Hanson gave up one run and one hit in four innings.
Atlanta's Jordan Parraz tied the game in the ninth inning with an RBI single, and the Braves scored twice in the 10th with the help of an error by second baseman Danny Espinosa.
Before the game, the Nationals said right-hander Stephen Strasburg will start opening day at the Chicago Cubs on April 5.