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A sweep of a day/night doubleheader and help from the Pittsburgh Pirates could help the Washington Nationals close the gap in the race for the second wild card spot.

Still, the Nationals enter Sunday a long shot to make the playoffs. Last night's contest against the Miami Marlins was washed out after a near four- hour rain delay before the contest ever started. That necessitated the second day/night DH for the Nationals in a week as they wrap a four-game set.

Washington comes into today 4 1/2 games behind the Reds for the second wild card spot. The Reds are in Pittsburgh today with those teams currently holding the two non-division leading playoff slots.

Dan Haren, who is 0-2 in three starts against the Marlins this season, gets the starting assignment for the Nationals in the afternoon contest. Haren is 1-5 in eight all-time contests versus the Marlins. He's 1-2 over his last five appearances overall

Tom Koehler, who is 0-4 over his last eight appearances, counters for the Marlins. The right-hander threw eight shutout innings against the Mets a week ago, but didn't get a decision. He suffered a 9-0 loss at Nationals Park on Aug. 29 when he allowed six runs on seven hits over five innings.

Rookie left-hander Brian Flynn goes for the Marlins in the night game. Flynn is coming off his second consecutive loss, 6-4 at Philadelphia on Tuesday when he allowed six runs on 11 hits over six innings.

Stephen Strasburg will make his final home start of the 2013 season in the night contest. The right-hander, who needs six strikeouts to reach 500 for his career, is 2-0 over his last seven outings and hasn't lost since July 30 at Detroit. Strasburg has a 6-3 mark with a 3.86 ERA in 13 games against the Marlins.

The Nationals have yet to lose at home in eight games to the Marlins this season. The Nationals have outscored Miami, 37-7 in DC.

Washington will finish its home schedule today. The Nats are 46-33 at home.

The Nationals are 13-4 against the Marlins this season and have prevailed in eight of the past nine matchups between the clubs.