ATLANTA -- Justin Nicolino turned in another impressive performance, taking advantage of a team that can't seem to do anything right.
For the rookie left-hander, it was the fourth straight start allowing two runs or less.
"I started off a little shaky," said Nicolino (3-2). "The command of the fastball wasn't where it needed to be. But I made a few pitches where my defense picked me up."
He shut down the Braves with help from a pair of double plays. Atlanta lost for the 14th time in 15 games, including the last seven in a row, but at least avoided its second straight shutout when A.J. Pierzynski drove in a run with a two-out single in the eighth off Erik Cordier.
"We all know where we stand," Pierzynski said. "It's not fun. But we'll be here tomorrow."
The Braves have been outscored 110-40 during their most recent skid. Manny Banuelos (1-3) got his first start in more than a month coming off the disabled list. He lasted 2 2/3 innings, giving up six hits and three runs.
Hector Olivera made his major league debut for the Braves. The touted Cuban defector went 0 for 4 with a strikeout.
Bour came up with a big defensive play and sealed the victory with a towering drive off Ryan Kelly into the Braves' bullpen, capping a four-run seventh that pushed the Marlins to a 7-0 lead. It was the first baseman's 15th homer of the season.
"Wow!" manager Dan Jennings said. "That ball was crushed."
Nicolino surrendered six hits, walked two and struck out three. The Braves squandered a couple of chances to break through.
In the first, Atlanta put runners at first and third before Nick Swisher grounded into an inning-ending double play. The Braves loaded the bases with no outs in the third, only to get burned by Nick Markakis' base-running blunder. He broke for second on a liner down the line, which was snared by a diving Bour. He hopped up and raced to the bag before Markakis had any chance of getting back. Freddie Freeman ended the threat with a groundout.
In addition to activating Banuelos from the DL and calling up Olivera from Triple-A Gwinnett, the Braves promoted three other players from the top minor-league team: RHP Dan Burawa, RHP Brandon Cunniff and IF Daniel Castro.
All but Cunniff got into the game. Castro started at shortstop and went 1 for 3, doubling in the seventh. Burawa pitched two perfect innings with four strikeouts in his second big league appearance.
The Marlins didn't call up anyone from the minors. Jennings noted that his team already had many of its top prospects on the roster.
Marlins: LF Christian Yelich returned to the starting lineup for the first time in six games despite a sore right knee. He went 2 for 4 with an RBI. ... RF Giancarlo Stanton, who broke his left hand in late June, was set to make his first rehab appearance in Tuesday's doubleheader for Class A Jupiter.
Braves: SS Andrelton Simmons (sore right ankle) missed his second straight game. Manager Fredi Gonzalez doesn't think the injury is serious, listing Simmons as day to day.
Marlins: LHP Adam Conley (2-1, 4.96 ERA) will be making his sixth start of his rookie season. In his only other appearance against Atlanta, giving up three runs in three innings of relief.
Braves: RHP Williams Perez (4-5, 5.56) will be looking to bounce back from the worst start of his short career. The rookie lasted just 1 2/3 innings against the New York Yankees, giving up eight earned runs in a 15-4 loss last Friday. He was sent briefly to the minors but will be called back up with the expanded rosters.
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