Washington @ Baltimore preview

Last Meeting ( May 28, 2013 ) Baltimore 3, Washington 9

When the Washington Nationals' Jordan Zimmermann takes the mound, he is all business. “It comes naturally. I’ve never been one to smile and have a good time out there, or make it look like I’m having a good time,'' Zimmermann told the Washington Post. Zimmermann will try to become the first nine-game winner in the majors when the Nationals visit the Baltimore Orioles on Wednesday. Zimmermann pitched with a sore neck in his last start but defeated the Phillies 5-2 on Friday.

Zimmermann will face Chris Tillman, who is 4-1 in his last six starts. The Nationals on Tuesday played their second straight game without right fielder Bryce Harper, who has bursitis in his left knee. He is unlikely to play Wednesday. Washington rolled anyway 9-3 behind four home runs - two by Adam LaRoche, including a three-run shot in the first inning. It was an unusual situation for Baltimore, which had outscored its opponents 43-19 in the opening frame entering the game.

TV: 7:05 p.m. ET, Mid-Atlantic Sports Network 2 (Washington), MASN (Baltimore)

PITCHING MATCHUP: Nationals RH Jordan Zimmermann (8-2, 1.71 ERA) vs. Orioles RH Chris Tillman (4-2, 3.68)

Zimmermann's success can also be traced to pinpoint command. He hasn't walked a batter in his last three starts and has yielded only nine in 72 2/3 innings. The 27-year-old Auburndale, Wis., native has pitched at least seven innings in eight of his 10 outings. Zimmermann is 1-2 with a 2.70 ERA in four starts against the Orioles - he last faced them in 2011 when he allowed two runs in 6 1/3 innings in a 4-2 victory. His ERA is second to only the Dodgers' Clayton Kershaw (1.68).

Tillman had a string of six quality starts snapped in his 10-6 victory at Toronto on Friday when he allowed three runs in five innings. He also matched a season best with seven strikeouts while yielding a season-high 10 hits. The 25-year-old Anaheim, Calif., native has not allowed more than three runs in his last seven turns and in eight of his 10 outings this season. Tillman faced Washington once and received a no-decision, allowing one run in five innings in Baltimore's 2-1 victory in 2011.

WALK-OFFS

1. Washington 2B Danny Espinosa could return to the lineup Wednesday. He has been out since May 22 with a fractured bone in his right wrist.

2. Baltimore 3B Manny Machado went 1-for-3 on Tuesday and shares the major-league lead in hits with Detroit's Miguel Cabrera (76).

3. The Nationals have homered in a major league-high 73 consecutive series.

PREDICTION: Nationals 3, Orioles 2