When first baseman Gaby Sanchez felt tightness in his left hamstring, Dobbs moved into his place and ended up driving in a career-high five runs in a 11-2 win.
"I should buy Gaby dinner tonight," Dobbs said. "I probably owe him that much, at least."
Dobbs drove in Florida's first run in the first on a groundout, scoring Omar Infante who had tripled. He hit a solo home run in the fifth inning, added a run-scoring single in the seventh and two more on a single during Florida's five-run ninth inning.
"It was a good move, right?" said McKeon with a smile after the game. "He's in there tomorrow. I'm not changing. It's perfect, give Gaby an extra day."
Dobbs also drove home a run in his other at-bat -- although he wasn't credited with an official RBI -- when he grounded into a double play in the third inning.
"We'll exchange a run for an out any day, I think," Dobbs said. "I would, as a hitter."
Logan Morrison and John Buck also homered for Florida, which scored at least 10 runs for the second time this season. The win also moved the Marlins (50-53) a half-game ahead of the Nationals and out of last place in the National League East.
"That's what we intended. That was our goal, get out of there," McKeon said. "The first step is .500, and then after that -- hold on to your hats."
Washington has lost three in a row and five of its last six. Since Davey Johnson took over as manager on June 26, the Nationals are 9-15.
"I see us as too good to stay in a losing streak so I keep waiting for everything to gel," Johnson said. "It's not sitting well with me. I have a high boiling point, and I'm getting closer to it."
Ricky Nolasco (7-7) rebounded from his worst performance of the season and pitched into the sixth inning, allowing two runs on three hits, as Florida won its third straight.
Nolasco, who allowed nine runs on nine hits in 1 1/3 innings his last time out against the Padres, held the Nationals hitless until Laynce Nix led off the fifth inning with his 13th home run of the season. By that time the Marlins offense had given Nolasco five runs of support.
"It's great to see those guys break out, and even better when you get an early lead," Nolasco said. "I'm just trying to go up there and let those guys put the ball in play and put us back in the dugout. Offensive support is very key."
Emilio Bonifacio led off the third inning with a double to extend his hitting streak to 24 games.
The Marlins led 6-2 after eight innings, and turned it into a rout in the ninth against Nationals reliever Henry Rodriguez, who gave up five runs on three hits and three walks. Rodriguez faced seven batters, and the only out was Hanley Ramirez's groundout which drove in a run.
Buck homered to lead off the ninth inning, the first of 10 batters Florida sent to the plate. Dobbs' two-run single came with the bases loaded and Mike Cameron also had an RBI single.
Jordan Zimmermann (6-9) gave up six runs on eight hits with five strikeouts. It was the second straight loss for Zimmermann, who also allowed six runs at Houston in five innings July 19. He had given up fewer than six runs in each of his first 18 starts this season.
"I know we're a better ballclub than we've shown at times," Johnson said. "When one of your pitchers doesn't do what he's capable of doing, when one of your relievers doesn't do what he's capable of doing, it gets ugly, and it's painful for everybody in this clubhouse."
Florida 1B Sanchez was out of the starting lineup for the first time this season and is day to day. ... The Nationals announced they had traded for Reds OF Jonny Gomes just before first pitch. The team sent two minor leaguers to Cincinnati in return for Gomes and cash considerations. ... Washington RHP Chien-Ming Wang is expected to start Friday, his first major league start since July 4, 2009. Johnson said Wang, who has been recovering from his 2009 shoulder surgery, will be activated from the disabled list Friday. ... The combined age of Marlins manager McKeon (80 years old) and Johnson (68) is 149 years and 57 days. That's the oldest for any managing pair since 1950, according to information provided from the Nationals from the Elias Sports Bureau.