Earlier this month, I wrote about the Milwaukee Brewers and how they stacked up with the rest of the National League Wild Card competition. The Brewers were four games down in the division at the time, and although they still had six games remaining against the Cubs, the projection systems only gave them a puncher’s chance at winning the NL Central.

But less than two weeks later, everything has been flipped on its head. Milwaukee is 6-2 in September, including 2-1 against Chicago in a contentious series at Miller Park where the rivalry was even called into question. The Brewers have now jumped into the first Wild Card spot and are actually closer to capturing the division lead than they are relinquishing their Wild Card position (two games behind Chicago, two-and-a-half games up on St. Louis).

A sweep this week at Wrigley Field would catapult Milwaukee into first place for the first time since July 31, but a series win should be the realistic goal. The Brewers have a soft schedule down the stretch – six games against Pittsburgh, three with Cincinnati, three at St. Louis, and three more at home against Detroit to close out the regular season – so it’s not unreasonable to think Milwaukee could outplay Chicago down the stretch as long as it doesn’t give up ground over the next three days. That will be easier said than done; the Brewers are just 1-5 at Wrigley Field this season.

This series could also be a potential playoff matchup in a few weeks. Chicago sits as the top seed in the NL right now, meaning they will play the winner of the Wild Card game, which of course currently sets up to take place at Miller Park. The Brewers have never played the Cubs in the postseason, but a five-gamer in the NLDS against Chicago would have I-94 buzzing all week long.

The playoffs can wait for now though; we’ll have a much clearer picture of the Brewers’ postseason outlook on Wednesday night. Here are the three keys to the Brewers-Cubs series.

Which pitching staff will stay hot?

The starting rotations for both Chicago and Milwaukee have been much maligned throughout the season. Both teams ultimately added veteran lefties – Cole Hamels and Gio Gonzalez, respectively – but neither are scheduled to toe the rubber in this series.

Even though it will be a host of familiar faces squaring off this week, all six pitchers are running hot heading into the series. For Chicago, Jon Lester has a 1.52 ERA in his last four starts; Jose Quintana owns a 2.38 ERA in his last four outings; and Kyle Hendricks has a 1.44 ERA in his past four starts. For the Brewers, Wade Miley has posted a 2.15 ERA across five starts; Jhoulys Chacin owns a 2.10 ERA in his last five outings; and Chase Anderson is the high-man of the group with a still steady 3.86 ERA in his last four starts. Runs will be at a premium through the first six innings of each matchup, even with plenty of All-Stars dotting each lineup card.

Ryan Braun heating up for the stretch run

Braun hasn’t been the same player for several seasons as injuries and age take a toll on his body, but he can still turn it on offensively when he is feeling good. Well, braun is apparently feeling good. Through July 23, the 34-year-old was slashing an abysmal .229/.275/.416; since then though, Braun is tearing up opposing pitchers, hitting .318/.395/.536 with 14 extra-base hits in his last 34 contests. Braun ranks 16th in the NL during that span with a .932 OPS as he has lowered his strikeout rate below even his peak MVP-levels.

When Braun is hitting the ball with authority, Craig Counsell can roll out a much deeper lineup each night. Lorenzo Cain and Christian Yelich are the two consistent stars atop the order, with a mix of Jesus Aguilar, Braun, Travis Shaw, Mike Moustakas, and Jonathan Schoop slotting in behind them. All seven players are capable offensive forces, but Braun hitting like the no. 8 of old goes a long way to boosting this unit.

And don’t expect him to cool off anytime soon. Braun has absolutely owned the Cubs throughout his career, particularly at Wrigley Field, where his .957 OPS is his best mark at any ballpark where he has played at least 40 games. Braun blasted two dingers off Quintana at Wrigley to key an August victory.

Brewers’ bullpen rounding into form

Over the first four months of the season, the Brewers’ pen was cruising along as one of the game’s elite groups. Through July, Milwaukee relievers collectively ranked fifth in the majors with a 3.30 ERA. That all fell apart in August, as the bullpen slipped to 28th in ERA (5.99), and even the infallible Josh Hader allowed a handful of runs.

But over the first chunk of September, the bullpen has returned to its previous levels of dominance, posting a 2.84 ERA with a stellar 11.9 strikeout rate thus far. Hader is still the linchpin from the left side, and Jeremy Jeffress continues to prove he is an elite pitcher when donning a Brewers uniform. But Corey Knebel’s bounce back could be the biggest key to Milwaukee’s push down the stretch; he has completed five scoreless innings with 10 strikeouts and zero walks in September, giving Counsell a reliable three-headed monster to close out games.

The Brewers’ plus-45 run differential is indicative of a 77-win team, rather than the 82 victories Milwaukee has already banked. The Brewers’ 29-18 record in one-run games has kept them on Chicago’s tail this season, and will be critical during this series and down the stretch, especially for a team whose starting pitchers who often only survive five or six innings.

Typically, just avoiding a sweep on the road against a team of Chicago’s caliber would be an acceptable result for the Brewers. But with the regular season ticking away, and no head-to-head opportunities remaining, the Brewers have to take at least two of three to have a legitimate chance to win the NL Central pennant. This is the biggest series of the year – at least until the next one.