It happens so often, you can almost mark it on your calendar: Every fifth day, when Jordan Zimmermann takes the mound, the Washington Nationals are going to struggle to score.

And so it was on Friday night, when the Nationals failed to produce a single earned run in a 2-1 loss to the Baltimore Orioles.

Zimmermann (3-6) gave up two runs and eight hits over seven innings. It was an impressive outing, except when compared to that of Baltimore's Jason Hammel, who tied a career high with 10 strikeouts and allowed five hits in eight solid innings.

Coming in, Zimmermann was receiving only 3.2 runs of support while in the game. This one only lowered the average — and hammered home a point.

"He's pitched great. We just haven't been scoring for him," Nationals manager Davey Johnson said. "We hit the ball hard today with runners on, got zilch.

Zimmermann gave up a second-inning solo homer to Mark Reynolds and a two-out RBI double to J.J. Hardy in the fifth. That was enough to keep him winless in five starts since May 28.

"He's 3-6. He's pitching a lot better than that, that's for dang sure," Johnson said.

Zimmermann isn't one to complain. He just does his job and hopes for the best.

"I just try to keep the team in it as long as I can and stay out there as long as I can and save the bullpen," he said. "I didn't have my best stuff tonight, but it was good enough to get through seven."

Coming off a one-hit shutout against Atlanta, Hammel (8-2) improved to 5-0 lifetime against Washington. He didn't top his outing against the Braves, but at least he built on it.

"It can't really get much better than that for me," Hammel said of his gem in Atlanta. "Obviously a no-hitter or a perfect game, but that didn't happen. I did basically the same thing, just come at them with two-seamers, aggressive in the zone, make them swing and put it in play."

Hammel, who did not issue a walk, has gone 19 straight innings without giving up an earned run.

"He was pretty nasty," Johnson said. "He had everything working."

After Hammel left, Jim Johnson got three outs for his 21st save.

Hardy gave the Orioles the lead in the fifth, then preserved it in the Washington seventh. With two on and two outs, the shortstop leaped high to snare Jesus Flores' liner.

"I jumped as high as I could and it just went into my mitt," said Hardy, who made a similar catch on Steve Lombardozzi's hard-hit ball in the eighth.

Davey Johnson last watched a game in the dugout at Camden Yards in 1997, when he guided the Orioles to the AL East title. He was fired after the season by owner Peter Angelos, and Baltimore hasn't had a winning season since.

"Managers are hired to get fired. All the times I was here were fun times for me," Johnson said before the game. "I really enjoyed playing here and learning the game of baseball here. It was fun to come back and manage in the town where I had played in. Played in a bunch of World Series here. My only regret was that I didn't get to manage the team in a World Series here. All my memories of Baltimore and baseball are nothing but great memories."

After the start was delayed 61 minutes by the threat of rain, Hammel pitched a perfect first inning and struck out the side in the second around a double by Michael Morse.

In the bottom of the second, Reynolds lined a 1-1 fastball into the seats in left to end an 0-for-11 skid.

Washington tied it in the fifth. Ian Desmond singled, rounded second base and took off for third on a groundout and scored on Reynolds' errant throw from first to third.

NOTES: The game drew a crowd of 45,891, the fourth sellout of the season at Camden Yards. ... Orioles LF Nolan Reimold will have neck surgery Monday and is likely lost for the season. He's been on the DL since May 4. ... Orioles RF Nick Markakis (hand) hasn't swung a bat since undergoing surgery three weeks ago, but says he expects to return to action before the All-Star break. .. Edwin Jackson (3-4) starts for Washington on Saturday against the Orioles, who will send rookie Wei-Yin Chen (7-2) to the mound. Chen is 4-0 at home but lost to the Nationals on the road last month.