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The Washington Nationals' starting pitchers are bailing out their struggling offense.

The Nationals rank next-to-last in the National League in batting average at .218 and 12th in runs, averaging 4.1 per game, but have been able to stay at .500 over the season's first three weeks due to a rotation that ranked fourth in the NL in ERA at 3.57.

"Obviously, there are guys with talent in this rotation," starter Jason Marquis said. "I'm not going to say we're the Roy Halladays or the David Prices of the world, but we do have some good pitchers."

The Nationals' game against the Pittsburgh Pirates on Friday night was postponed due to rain, and the teams will make it up 7:05 p.m. Monday on what was a common off day.

With this and the rainouts in Baltimore and Minnesota, there have been 15 postponements in the majors this season, just six shy of the total for all of 2010, according to STATS LLC.

Each team will simply move its starting pitchers up a day and stay on the same rotation. As a testament to how strong Washington's rotation has been, each of the series' three starters has an ERA of less than 3.50.

"More than anything, we've become quality strike throwers," Marquis said. "We're not messing around or dancing around the strike zone; we're attacking the strike zone. On top of that, we have a good defense and that's important. We're a staff that pitches to contact. When the ball is put in play, there is a very good chance that the play is going to be made."

Marquis has pitched at least six innings and has allowed no more than three runs during each of his three starts this season after being limited to only 13 starts due to an elbow injury last year.

Right-hander Jordan Zimmermann, the team's 2008 minor league pitcher of the year, appears to finally be fully recovering from Tommy John surgery in 2009.

Veteran Livan Hernandez has been durable, as usual, and lefty John Lannan has finally shown consistency since a midseason demotion to the minors last year. Left-hander Tom Gorzelanny was added in an offseason trade with the Chicago Cubs to fill out a rotation that has avoided the poor outing: Washington's starter has pitched at least five innings in every game this season.

"They're healthy, No. 1," manager Jim Riggleman said. "Last year, we had two or three guys who weren't expressing that they had some discomfort there. They pretty much have that behind them and are taking the ball every time out every time without feeling any pain. They are able to take their bullpen sessions, keep their mechanics together and are in a real good flow right now."

Hernandez (2-1, 2.88) will face Pittsburgh's Jeff Karstens (1-0, 4.50) in what is now the series opener Saturday. Sunday's matchup will be Marquis against Kevin Correia and Monday is Lannan vs. Paul Maholm.

By the end of the series, Nationals pitchers likely will be facing a new shortstop in the Pirates' lineup.

The Pirates claimed infielder Brandon Wood off waivers from the Los Angeles Angels on Friday. Wood was formerly one of the game's top prospects but has struggled mightily with the bat at the major league level.

Wood has displayed a power stroke that has had him hit .284 with 161 home runs in 764 minor-league games — including 43 in 2005 in Single-A. He also is known as a more-than-capable defender, having played mostly shortstop and third base over 173 games in the majors.

But his offense hasn't translated to the majors. In parts of the last five seasons with the Angels, Wood has 11 home runs and 33 RBIs in 173 games — but he's a career .168 hitter.

"I know things haven't really (transpired) the way he hoped," Hurdle said. "He's a solid defender. He can play three positions. His bat is the question. The opportunity, probably, with the Angels probably wasn't as long as he liked or what they would have liked to have given him.

"We'll give him time in the batter's box and see if we can help him make a difference, re-ignite the swing."

Hurdle said Wood would play regularly — likely at shortstop in lieu of the struggling Ronny Cedeno, who's hitting .170 with one extra-base hit in 53 at-bats. The Pirates' hope is that a change of scenery will do Wood good.

"Sometimes, something as simple as that can help," Hurdle said.

Wood, who was 2 for 14 with a double in six games this season, was designated for assignment by the Angels on Wednesday.

The Pirates on Friday also recalled Pedro Ciriaco from Triple-A Indianapolis. Hurdle indicated that Ciriaco would only be with the team until Wood arrived, which is expected by the end of the weekend.

Pittsburgh designated infielder Josh Rodriguez for assignment. A Rule 5 pick from Cleveland, he now must be offered back to the Indians.

Notes: Nationals prospect Bryce Harper had 6 RBIs in Friday night's game for Hagerstown of the Class A South Atlantic League. ... Washington will recall infielder Brian Bixler, a former Pirates player, before Saturday's game. Bixler was with the team Friday after he hit .326 in 14 games for Triple-A Syracuse. He hit .178 in 68 games with Pittsburgh in 2008-09. ... Riggleman said reliever Todd Coffey (thigh) will be activated from the disabled list Sunday when he's eligible, assuming he has no problems performing pregame running drills Saturday.