CHICAGO -- September came a day early for the Brewers, who figure to use the whole roster in an attempt to stay in the National League playoff picture.

Saturday’s 2-0 win over the Cubs began with a first-inning rally started by a leadoff man, Ben Gamel, who was called up early from the Minors to help cover a spate of injuries, and ended with a four-man, 13-out bullpen effort that offered a preview of the expanded roster matchup mania to come.

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As a result of a victory with Keston Hiura on the injured list, Mike Moustakas sidelined by a hand injury and Ryan Braun (back) and Lorenzo Cain (knee) limited to pinch-hit duty, the Brewers find themselves 6 1/2 games back of the Cardinals in the NL Central and moved back to within four games of the Cubs for the second NL Wild Card.

“You kind of knew going in that it was going to be that style of a game,” said Milwaukee starter Zach Davies, who worked 4 2/3 scoreless innings before manager Craig Counsell handed the game to his relief corps. “From here on out, every game is pretty important. You don’t want to put more emphasis on these games, but these are the only games you have left. There comes a time when you have to put the foot on the gas and start to go.”

Davies added, “We’re still in it. We’re down a little bit, but we’re still in the playoff hunt. Still alive. Guys will continue to step up like they have all year.”

More reinforcements will arrive Sunday when rosters expand to 40 for the final time -- beginning in 2020, teams will be limited to 28 active players after Aug. 31. The Brewers plan to make liberal use of the extra help, like they did out of necessity on Saturday after summoning outfielder Gamel and infielder Travis Shaw from Triple-A San Antonio and putting them right to work in a huge intra-division game against the Cubs. Gamel promptly punched a leadoff double over third base against Cubs starter Cole Hamels for the first of Gamel’s three hits, and Manny Piña muscled a two-run single over the left side of the infield.

Davies and the Brewers’ bullpen insured the lead stood. Davies pitched 4 2/3 innings on 77 pitches before yielding to Matt Albers, Drew Pomeranz ,Junior Guerra and Josh Hader, who secured Milwaukee’s sixth shutout this season.

Guerra and Hader were particularly impressive, combining to retire all 10 men they faced on 29 total pitches. Guerra pitched parts of three innings, starting with the bases loaded and two outs in the sixth, when he induced an Addison Russell comebacker that ticked off Guerra’s glove before he recovered and flipped to first base to end the threat.

Cubs manager Joe Maddon still considers the division a three-team race.

“Of course, absolutely I do. They play us tough,” Maddon said. “You can't discount their defense. They have played well against us on the other side of the ball. They have a lot of good names over there. I know Moustakas has been hurt. They want him back badly, I'm sure. Cain came in late. Braun. They beat us today without two of their better right-handed hitters, also against a left-handed pitcher. So, they've got to take some solace in that, too.”

The Brewers won with pitching, starting with Davies. He entered the day with losses in each of his previous five starts, a streak that was poised to end Saturday had he been given the opportunity to complete the fifth inning.

“Look, today is a day we know we have a bunch of fresh guys coming tomorrow,” Counsell said. “We planned today out to be a really aggressive day. I told Zach before the game we’re going to have to be really aggressive. There’s going to be some days we can do it, and other days we’re a little taxed that we can’t.”

Two of the Brewers’ September pitching additions, Jimmy Nelson and Brent Suter, were already at Wrigley Field on Saturday. Other pitchers will join them Sunday; Jake Faria, Freddy Peralta and Taylor Williams are among the arms already on the 40-man roster with a chance to have their name called. Teams typically call up an extra catcher on Sept. 1; David Freitas and Jacob Nottingham are both on the 40-man.

The Brewers reached the month of September with a 69-66 record. It’s shakier footing than a year ago, when Milwaukee entered the final month 16 games over .500, four games behind the first-place Cubs in the division and jockeying with the Cardinals atop the Wild Card standings. As of Aug. 31 last year, the Cardinals held the top Wild Card spot and the Brewers were a half-game back, with a 2 1/2-game cushion on the next team.

According to FanGraphs’ calculations at the time, the Brewers’ postseason odds were 75 percent. After Saturday’s win, they are at 9.5 percent entering September.

Do they have a magical run in them?

“It’s not magic. It’s good baseball,” Counsell said. “Today, we played a solid baseball game. We played really nice defense, we pitched really well, we got a hit when we needed in kind of tough offensive conditions, and it stood up.

“That’s good baseball. We’re capable of that, and that’s what it’s going to take.”