ATLANTA — The Atlanta Braves are shaking things up after a September flop cost them a second straight trip to the playoffs.

The first change came Friday: hitting coach Larry Parrish was fired after only one season. The timing of the announcement was a surprise, coming one day after manager Fredi Gonzalez said his entire staff would return in 2012.

As it turns out, everyone is returning but Parrish, who was dumped even though he had another season left on his two-year contract. Several hitters regressed noticeably under his tutelage, and the Braves finished 13th in the NL in batting (.243) and 10th in runs.

Braves general manager Frank Wren also said it’s not certain that Derek Lowe will have a spot in the rotation next season, even though the team still owes him $15 million on the final year of his contract.

The 38-year-old right-hander had a miserable season, going 9-17 with a 5.05 ERA.

On a similar note, Wren said right fielder Jason Heyward will have to fight to keep his job in spring training after hitting just .227 with 14 homers and 42 RBIs.

The firing of Parrish wasn’t necessarily unexpected, but the way it was handled reflected an apparent breakdown in communication between Gonzalez and Wren.

The general manager said “we couldn’t go forward with 2012 without changes,” including a new hitting coach. Wren promised “an exhaustive search” for Parrish’s replacement.

“I felt we weren’t on the same page philosophically,” Wren said. “I’m not sure the message got through to the players.”

The Braves’ lack of offense was a big problem all year, and really came to the forefront in September as the Braves squandered an 8«-game lead. Atlanta averaged just over three runs a game and hit under .200 with runners in scoring position over the final month.

More troubling, several players dropped off considerably from the previous season, including 2010 All-Stars Heyward and Martin Prado (from .307 to .260).

Heyward homered in his first career at-bat and finished second in the NL Rookie of the Year balloting as a 21-year-old, hitting .277 with 18 homers and a .393 on-base percentage. His on-base percentage plunged to .319 this season, and he struggled to make adjustments the Braves feel are critical to his long-term success.

Now, instead of being the future of the franchise, he’s not even guaranteed a starting job next season.

“He’s going to be in a battle. It’s not a given he’s our right fielder,” Wren said. “He’s a young guy with a lot of potential. General managers say potential is good, but we need production.”

Wren, however, did stress that there’s been no discussions about trading Heyward.

Lowe will be in a similar position next spring. The Braves have an abundance of talented young pitchers and won’t show nearly as much patience as they did this year, when Lowe made every scheduled start even though he never sorted out a breakdown in mechanics. He lost all five of his September starts, a major culprit in the Braves giving away a seemingly comfortable lead in the wild-card race.

“It’s hard to project him as one of our starters at this point,” Wren said.

The Braves had held at least a share of the wild-card lead since June 9 until falling behind on the final day of the season with a 13-inning loss to Philadelphia, according to STATS LLC. Atlanta went 9-18 in September and finished one game behind St. Louis.