In a tie game entering the bottom of the seventh, Vladimir Nunez came out of the bullpen with a man on first and yielded two runs -- one charged to him -- and Atlanta was held scoreless the rest of the way by Florida's relievers for a 5-3 loss in front of 11,211 at Dolphin Stadium.
The Braves went 10-8 in the season series against the Marlins, and have now dropped 13 of their past 17 games. After posting a 6.13 ERA in August, the bullpen has already given up 10 runs in 11 1/3 innings through three games in September, and the relievers are now 15-24 this season.
"Any time you lose [this many] games in a year, you get to a point where you're repeating yourself," said catcher Brian McCann, who finished 0-for-4. "We were in the game the whole time, and the bottom line is they outscored us."
After going 1-2 in the three-game series against Florida -- and 1-5 over the six-game road trip -- Atlanta (60-80) returns home 20 games under .500 with 22 contests remaining. The last time a Bobby Cox-led team was 20 games under .500 was 1979, when Cox was in his second season as a big league manager.
"I don't really think about it," Cox said. "I think about today's game and tomorrow's game."
Wednesday's loss was pinned on Will Ohman, who started the seventh inning and gave up a leadoff single to Jeremy Hermida in a 3-3 game before Nunez was given the nod.
After that, Nunez retired the first batter he faced, gave up a double to right field by Hanley Ramirez and intentionally walked John Baker to load the bases. The Marlins' next batter, Cody Ross, singled to center field to give Florida the lead, and Ramirez scored five pitches later when Nunez's splitter in the dirt scooted a couple of feet behind McCann, who initially didn't see it.
After scoring three runs in the fourth inning, only three Braves reached base against three Marlins relievers in the final three innings to end the game.
"[The Marlins] have a good bullpen," said McCann, whose offense was without Chipper Jones for the second consecutive game because of a twisted right knee. "They did their job. They went out there and put up scoreless innings."
Atlanta took a 3-1 lead with three runs in the top of the fourth. After Yunel Escobar singled -- and was later taken out of the game with an aggravated left shoulder -- Omar Infante got a base hit and Kelly Johnson -- who went 4-for-5 with four RBIs on Tuesday -- tripled to plate two runs and give the Braves a 2-1 lead. Jeff Francoeur followed with a base hit up the middle, which he stretched into a double, to give Atlanta a two-run lead.
Starter Jorge Campillo had his streak of 12 shutout innings at Dolphin Stadium snapped when he gave up a solo shot to Ramirez with two outs in the third inning. In the fourth, Campillo -- one start removed from giving up five runs in 3 2/3 innings to the Nationals -- surrendered the lead by giving up two-out RBI singles to Josh Willingham and Hermida before exiting after five innings.
But the 30-year-old right-hander isn't ready to pin the Braves' trying season solely on the relievers.
"I put a lot of the responsibility on the starters, because we've been leaving the games too many times before the fifth inning," Campillo said. "I notice that the bullpen is really tired, because pretty much every game, they're throwing four, five innings. And I feel like we need to go longer so they can be fresher."
Cox added to his all-time record for ejections when he was rung up for the 143rd time to start the top of the fifth. Cox started arguing a strike call with home-plate umpire Mark Wegner after the first pitch of Martin Prado's at-bat and was tossed for the eighth time this season.
Alden Gonzalez is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.