Their offense could continue to have trouble in the middle contest of the Beltway Series.
Edwin Jackson, the owner of the lowest ERA of the Nationals' stellar starters over the last six weeks, takes the ball against one of his favorite opponents Saturday night in Baltimore.
After totaling three runs and 12 hits while being swept in three games by the New York Mets this week, the Orioles (40-30) did little to show they were busting out of their slump Friday. Mark Reynolds homered and J.J. Hardy hit a run-scoring double, and that was all the offense Jason Hammel needed in a 2-1 victory as Baltimore pulled within 1½ games of AL East-leading New York.
"We hit the ball hard with runners on, got zilch," said Washington's Davey Johnson, who was managing his first game at Camden Yards since 1997, when he guided the Orioles to the AL East title.
The Nationals (40-28), who own a 2½-game lead in the NL East, lost for the fifth time in seven contests, and the heart of their order is struggling mightily. No. 3 hitter Ryan Zimmerman is batting .114 over his last 11 games, while cleanup hitter Adam LaRoche is mired in an 0-for-14 slump.
The Orioles are experiencing similar problems, with No. 3 hitter Chris Davis hitless in his last 24 at-bats and cleanup man Adam Jones 2 for 15 in his last four games and without an RBI in his last nine.
Jones hasn't had much success against Jackson (3-4, 3.02 ERA), going 4 for 17, while Davis and Matt Wieters have had virtually none, combining to go 0 for 26 with nine strikeouts.
Jackson has yielded two earned runs or fewer in each of his last four starts, and has a 2.63 ERA -- the best on the team among the starters -- in eight games since May 8. The right-hander is just 2-3 in that stretch, though, after allowing two runs in six innings of Sunday's 4-1 loss to the Yankees.
"All in all, I came off the field giving the team a chance to win," Jackson told the Nationals' official website. "As a starter, that's your job."
He pitched even better but didn't get the win May 18 against Baltimore, yielding a run and five hits with eight strikeouts in eight innings of a 2-1, 11-inning loss. That kind of dominance over the Orioles has been commonplace lately, as Jackson is 3-0 with a 0.95 ERA in his last five starts against them.
Wei-Yin Chen's worst outing of an otherwise solid rookie season came at the hands of the Nationals.
In Washington on May 20, Chen (7-2, 3.36) was knocked around for six runs and eight hits in 4 1-3 innings of a 9-3 loss. Bryce Harper went 2 for 3 with a triple off the Taiwanese left-hander, while Jesus Flores homered.
Harper is 1 for 12 in his last four games and hitless in his last 12 at-bats against lefties. He had been batting .400 against southpaws before that.
Chen, 4-0 with a 2.72 ERA in six home starts, takes the mound after pitching seven innings in Sunday's 2-0 win at Atlanta. He has posted a 2.21 ERA in winning his last three starts after going 0-2 with a 7.31 ERA in the previous three.
"Chen-sational," Jones said.
Copyright 2012 by The Associated Press
This story is from ESPN.com's automated news wire. Wire index
MORE MLB HEADLINES
- Mets rookie P Wheeler wins 1st career start
- Red Sox put P Buchholz (neck strain) on DL
- Yanks' Tex goes on DL; surgery for Youkilis
- O's homer twice off Verlander to top Tigers