MILWAUKEE -- Twenty games. That is all that remains on the Cubs' regular-season schedule. That is all the time Chicago has left to do what it can to sort through its growing pile of issues, piece together a solid stretch of baseball and punch its ticket to the October stage.

"Time's ticking," Cubs pitcher Cole Hamels said earlier this weekend.

On Sunday, another nine innings ticked away and the Cubs absorbed an 8-5 loss to the Brewers at Miller Park. The North Siders took the opener on Thursday, but then slipped back into a familiar offensive lull as injury problems mounted. In the finale of the four-game set, veteran Jon Lester was saddled with eight earned runs.

• Box score

With the loss, the Cubs slipped to 4 1/2 games back of the National League Central-leading Cardinals, who will face Chicago seven times in the final 10 games of the season. The Cubs are now three back of the Nationals, who occupy the NL's top Wild Card spot.

The Cubs lead a pack of teams vying for the second Wild Card, with the D-backs 1 1/2 games in the rearview mirror. The Brewers, who have won five of seven against Chicago over the past 10 days, are now two back of the NL’s last postseason spot, along with the Phillies.

"Other teams have played better than us," Lester said. "The Cardinals, I think I saw something the other day, they've had the best record since the All-Star break. So, they've flat-out played better than us. These guys seem to play us extremely difficult. Now, you've got the D-backs making a run. Obviously, the Phillies are right there.

"That's the exciting part about having two Wild Card spots. Now, you've got four or five teams involved as opposed to just one. We've got to buckle down and play better."

Clinging to October aspirations of their own, the Brewers looked at this recent stretch of games as a seven-game series against the Cubs.

"That’s what we had to do at a minimum, was to win the series," Brewers manager Craig Counsell said. "And we did it. It gives us a big week of baseball ahead of us, and they earned that."

And Milwaukee caught the Cubs in a stretch riddled with setbacks, too.

Sept. 1: Yu Darvish was scratched with tightness in his right forearm, Javier Báez injured his left thumb on a stolen base and closer Craig Kimbrel felt discomfort in his throwing elbow.

Tuesday: Kris Bryant was scratched from the lineup with right knee soreness, which has been an off-and-on issue dating back to late June.

Thursday: Baez was in the original lineup against the Brewers before being scratched with persistent pain in his hand. Kimbrel was placed on the injured list with inflammation in his elbow.

Saturday: An MRI exam on Baez in Chicago revealed a hairline fracture in his right thumb, putting the rest of the season at risk for the shortstop. He will see a hand specialist on Monday. On the same day, interim shortstop Addison Russell made a critical ninth-inning error in a walk-off loss.

And now on Sunday, Bryant was scratched from the lineup again due to the same knee injury, following a foul ball off his right leg in the previous game. Then in the third inning, Russell was hit in the head by a pitch from Adrian Houser and taken out of the game a half-inning later. That forced utility man David Bote into emergency duty at short.

Russell is under evaluation for concussion symptoms, but was cleared to fly to San Diego with the Cubs for their upcoming four-game series with the Padres.

It has been a lot for the Cubs to tackle under the heightened pressure of a playoff chase.

"Honestly, there's only one way to deal with moments like this, and that is in the moment," Maddon said. "Anxiety lives in the future. You've got to stay right here, right now. Things can change just as quickly. We could win the first three games in San Diego easily and other teams could lose. You've just got to take care of yourself on a nightly basis."

While Maddon insists that "the run is in the runs," meaning the offense is a driving factor for any success the Cubs have down the stretch, Chicago also knows the tone needs to be set by the rotation.

In the past four games in Milwaukee, the starting staff combined to allow 17 earned runs in 18 1/3 innings, and that includes five shutout frames logged by Darvish in his return to the mound on Saturday. Hamels was roughed up in 3 1/3 innings on Friday and Lester, despite working into the sixth inning, allowed at least six earned runs for the fifth time this year.

The breaking point was a five-run fourth inning, which was capped off by a three-run, pinch-hit homer off the bat of Tyler Austin.

"All we can do is show up and play," Lester said. "Hopefully, I pitch better. That's all you can do. You can't sit here and mope and complain about this."

After all, time's ticking.