ATLANTA -- With the uncertainty surrounding Stephen Starsburg's right elbow, the Washington Nationals may have a greater need for Gio Gonzalez to come through in the postseason.

The veteran left-hander's turnaround from a dismal middle of the season has made that thought a little less scary for Nationals fans.

Gonzalez, who is 11-9 with a 4.27 ERA, has allowed three earned runs or less in 11 of his past 13 outings going into Saturday's start against the Atlanta Braves in the Nationals' next-to-last game at Turner Field.

Gonzalez is 6-2 over the stretch and is coming off a victory against the Philadelphia Phillies last Sunday in which he allowed just one run and four hits over seven innings.

"He seemed like a guy on a mission," Washington manager Dusty Baker said Sunday. "We talked the other day, and I told him that he's very important in this equation, especially with Stras out. He responded."

It was only the fourth time this season that Gonzalez made it through seven innings and he did it on just 92 pitches He got 10 outs on the ground thanks to a pair of double plays.

If Strasburg can't pitch in the postseason, the Nationals would likely be left with Gonzalez as their third starter behind Max Scherzer and Tanner Roark, and it has definitely been an up-and-down season for the veteran, who turns 31 on Monday.

Gonzalez had a 1.86 ERA through his first eight starts, an 8.10 ERA over his next eight starts, then a 3.10 ERA during his past 11 outings.

Gonzalez's worst start recently came against the Braves in Washington on Sept. 6, when he gave up six runs in three innings.

"My last start didn't go that way," Gonzalez said. "A good bounce back. I just wanted to have a good bounce back. As long as I can keep going deep in the game that is important."

He allowed just three hits over six scoreless innings against the Braves in a no-decision April 12 and is 4-8 with a 4.70 ERA in his career against Atlanta.

Gonzalez will try to help the Nationals inch closer to clinching the NL East. After Trea Turner had four hits and scored four runs and Max Scherzer won his fifth straight decision in Friday's 7-2 win, the Nationals lowered their magic number to six with 15 games remaining.

Turner is hitting .462 in 11 games against the Braves. The 23-year-old's third four-hit outing raised his average to .349 in 58 games.

"Trea had his fingers all over it again," Scherzer said. "This guy can absolutely do everything. I've never seen anybody with this much speed and power from that (slight) frame. He impacts the game is so many different ways. We're asking him to play center field off and he's excelling at that.

Josh Collmenter, acquired by the Braves from the Chicago Cubs organization, will start Saturday against the Nationals. He is filling for Mike Foltynewicz, who was hit in the left calf by a line drive on Monday.

Collmenter made 15 relief appearances for the Arizona Diamondbacks this season before being released. He signed a minor league deal with the Cubs and made four starts for Triple-A Iowa.

The 30-year-old right-hander had a 36-33 record and 3.54 ERA in parts of six seasons with Arizona. He won 10 games in 2011 and 11 in 2014 for the Diamondbacks.

The Braves will have first baseman Freddie Freeman back in the lineup after he missed Friday's game to be with his wife, Chelsea.

She gave birth to the couple's first child, a boy named Frederick Charles Freeman II, on Thursday after a long labor.

"The baby's here, everybody's doing good, but I understand it wasn't an easy go," said Braves interim manager Brian Snitker, who told Freeman to skip the series opener against the Nationals. "He needs to regroup."

Freeman left at the start of the eighth inning Wednesday against the Marlins after extending his hitting streak to 20 games. He also has a 36-game streak of reaching base safely.

Freeman has usually been at his best against the Nationals, hitting .325 with 12 home runs and 54 RBIs during his career.