Traber shut the Marlins out over the first six innings, but a disastrous seventh inning in which he allowed three runs marred what was likely his strongest start of the season.
"Traber pitched a [great] ballgame," Nationals' manager Frank Robinson said. "He didn't give up a lot of opportunities."
In the seventh, though, Traber gave a big opportunity to the Marlins. After getting out of a bases-loaded jam in the sixth unscathed, Traber ran into trouble again in the seventh, giving up an RBI triple and single to Hanley Ramirez and Dan Uggla, respectively, that put Florida up, 2-1.
Traber came out of the game after Uggla's single, and reliever Jon Rauch then gave up a single to Miguel Cabrera that drove in Uggla when Alfonso Soriano bobbled the ball in left field.
"I just made some bad pitches when I should've made good pitches and they capitalized on it," Traber said.
Despite the rocky seventh, Traber (3-2) looked effective, holding the Marlins scoreless over six innings. Making just his third start since being called up from a three-month stint at Triple-A New Orleans, Traber struck out six batters prior to the seventh, and held the Marlins to three hits.
Coming back from the short rain delay, though, Traber showed signs of shakiness.
He walked two batters and hit another with two outs in the sixth, but managed to force a foul popout to first base to get out of the jam before the three-run seventh.
"He seemed to be off his rhythm a little bit when we came back, but it wasn't a long delay," Robinson said.
The Nationals offense seemed to be off throughout the entire game. After showing little signs of life before the rain delay, the Nationals had a big chance to jump on the Marlins. Following the rain delay in the sixth, Soriano hit a leadoff solo home run to break up a scoreless tie. Marlins starter Anibal Sanchez then walked Felipe Lopez and Ryan Zimmerman with no outs, and the heart of the Nationals' order coming to bat.
Sanchez managed to buckle down, though, and retired the next three batters to get out of the potential jam.
"We just didn't take advantage of our opportunities over the course of the game," Robinson said. "It's a mental thing and a physical thing. Mentally, it's just that you don't focus in on what you want to do."
Holding a slim 1-0 lead with one out, Traber hit Jeremy Hermida with a pitch that the Marlins outfielder appeared to lean in on. Robinson came out and argued that point, but to no avail. The hit batsman proved to be a turning point, as Ramirez tied the game with an RBI triple that drove in Hermida.
"[I was] just trying to get a ground ball, get him out," Traber said. "That's what I was trying to do, [but] it didn't work very well."
Uggla lined a single up the middle in the next at-bat to give the Marlins a 2-1 lead. Following Uggla's base hit, Traber came out of the game and was replaced by Rauch, who gave up the single to Cabrera that allowed Uggla to score on Soriano's error.
"It just got caught in my glove and then I dropped the ball," Soriano said.
Rauch caught Josh Willingham swinging for the third out, but by that point the damage was already done.
Aside from a walk to pinch-hitter Marlon Anderson in the ninth, the Marlins retired the Nationals in order over the next two innings to seal the loss.
"It's just the way it goes sometimes," Austin Kearns said. "You go through those times where you're getting those big hits, and then you go through times like this. It's tough."