The left-hander grooved an 89-mph fastball to Bryan Petersen, who ripped it over the right field fence for his first career walk-off home run. It gave the Marlins a 3-2 win and gave Javier Vazquez his second consecutive complete game against the Nationals.
For Slaten, it continued a disappointing season after he became a solid lefty specialist in 2010. He has a 4.41 ERA and missed 75 games with left elbow neuritis. Petersen's homer off of him on Tuesday dropped the Nationals to 79-81, guaranteeing they'll finish with their sixth consecutive losing season.
Slaten might have given up the final blow, but the Nationals did plenty of other things to cost themselves a win. They had just four hits off Vazquez, who will reportedly retire after the game, and put only two runners in scoring position all night. Michael Morse tied the game with a home run in the fifth inning, and the Nationals took a 2-1 lead in the sixth, but the Marlins scored the game-tying run on John Lannan's wild pitch in the sixth.
More from the clubhouse in a little bit.