CHICAGO -- When the Cubs arrive at Miller Park in Milwaukee on Thursday, it will mark the beginning of a 24-game sprint to the regular-season finish line. Chicago has work to do if it wants to avoid another National League Wild Card Game and instead reclaim a division title.

"It's in our own hands," Cubs outfielder Kyle Schwarber said.

Chicago entered Wednesday's off-day three games back of the NL Central-leading Cardinals, whom the Cubs will face seven times within their final 10 games this season. Starting with this weekend's four-game set with Milwaukee, Chicago plays division foes 20 times down the stretch.

As the Cubs stare down that end-of-season slate, here are three positive developments and three causes for concern that have emerged recently.

THREE UP

1. Schwarber's approach

Schwarber has fallen into three-true-outcome mode plenty of times in his career. Mash a homer, draw a walk or go down swinging hard. As this season has progressed, though, the Cubs' left fielder has improved his plate discipline and cut down on the strikeouts. Take a look at Schwarber's monthly strikeout rates:

March/April: 29.7 percent
May: 27.7 percent
June: 26.1 percent
July: 19.5 percent
Aug.-present: 21.6 percent

Schwarber's rate of swinging at pitches outside the zone has dropped to 21.5 percent since Aug. 1 -- down from 27.7 percent in July and 31.4 percent in June. He has hit to the opposite field (29.9 percent) more often than in any other season in his career, too. Since Aug. 1, the result has been a .287/.392/.678 slash line for the Cubs.

2. Wi(e)ck-ed curveballs

The Cubs acquired right-hander Rowan Wick from the Padres over the offseason, and he has emerged as a reliable late-inning arm this season. Chicago reeled in lefty Brad Wieck from San Diego at the Trade Deadline, and he has been an intriguing September addition. What do they have in common besides a last name that is pronounced the same? They both now throw a knuckle-curveball. The Cubs put both Wick (in Spring Training) and Wieck (last month) in their pitching lab and had them ditch the traditional curve.

"Once you get your pointer finger out of the way, we noticed that the spin rate went up," Wieck explained. "So I'm just trying to spin the ball better and with better spin efficiency. It was kind of a gyro spin -- my curveball was kind of spinning like a slider. We got the pointer finger out of the way, and now it's moving more end over end."

Wick's curveball has had an average spin rate of 2,583 rpm this year with the Cubs, compared to 2,298 last season with the Padres. Similarly, Wieck's curve has jumped to 2,360 rpm on average so far in September, compared to 2,174 earlier this year with San Diego. Both relievers are poised to factor into the Cubs' 2020 bullpen plans.

3. Change at the top

The Cubs entered Wednesday's off-day ranked 30th in the Majors with a .283 on-base percentage and 71 wRC+ out of the leadoff spot this year. This comes after Chicago was one of the better teams in terms of production out of the No. 1 slot (.366 OBP and 121 wRC+) in 2018, using a similar matchup-based approach. The return of Ben Zobrist, who offers a contact-oriented style that has been missing in the Cubs' lineup, should help the leadoff numbers trend in the right direction. He was a big part of last year's success out of the leadoff spot, and he showed in Tuesday's win (walk, bunt single and an average of five pitches per plate appearance) that he still has his strike-zone discipline.

"It's definitely a learned skill," Zobrist said. "It's something that you've got to really focus on, try to be disciplined on. Thankfully, it's not something that just goes away when you haven't been around for a while."

THREE DOWN

1. Bryant's nagging knee

The last thing the Cubs' inconsistent offense needs right now is seeing Kris Bryant's slugging percentage sapped due to an injury issue again. That was the case in 2018 with a left shoulder problem. Right now, the third baseman is dealing with persistent right knee soreness. Bryant was scratched from the lineup on Tuesday, and he will be re-evaluated Thursday in Milwaukee. Dating back to July 24, when he left a game against the Giants with the ailment, Bryant has slashed .229/.299/.397 in 35 games. He's hit .196/.268/.314 over the past 14 games. Chicago is hoping a few rest days help alleviate the discomfort.

2. Darvish's recent forearm issue

The Cubs insist that the right forearm tightness that cost Yu Darvish his start on Sunday was not a major issue. And as things stand, the right-hander is in line to start on Saturday as planned against the Brewers. That said, red flags are definitely raised when the forearm is cited as the problem for a pitcher with a history of past elbow injuries. Darvish's in-season turnaround (3.19 ERA, 78 strikeouts and three walks in his past 62 innings/10 starts) has been critical for Chicago's rotation, and he remains an important piece for the stretch run, and potentially, October. Needless to say, his outing on Saturday will be monitored closely with the next few weeks in mind.

3. Where has Strop gone?

This has been a turbulent season for Pedro Strop, who has lost his footing as the Cubs' primary setup man. The right-hander hasn't pitched in a high-leverage, late-inning moment since Aug. 15, and he has spent this summer battling health setbacks and searching for his fastball velocity. On Sunday, Strop averaged 93.4 mph with his four-seamer, per Statcast. That was up from 92.5 mph three outings earlier. It sounds surprising, given his long history of success with Chicago, but Strop has three weeks to show he can be trustworthy in a big spot in a postseason setting.