The quarter-mark of the 2021 campaign has come and gone, and with it, plenty of early-season conclusions can be made. The Cardinals are proving the class of the NL Central. The Brewers' offense could use a pick-me-up. The Cubs, as expected, are not making their future trajectory path any clearer.

Bu with some early-season conclusions come some longer-term questions -- and many that will linger until the All-Star break in mid-July and Trade Deadline on July 31.

This week, each NL Central beat reporter identified the biggest looming question for their club after the quarter-mark of the season:

Brewers: Why aren’t they hitting?

“New school” general managers like Brewers president of baseball operations David Stearns tend to push every decision to the deadline, but he should know by the All-Star break whether the team needs a bat or two at the non-waiver Trade Deadline several weeks later on July 31. So far, the Brewers lineup is not working, even when you put it in context with the suppressed offensive numbers across baseball. After ranking at or near the bottom of the NL in most run-production categories last year, the Brewers are there again, including the league's worst batting average and a near-worst strikeout rate. The question is what to do about it: Empty the farm system again to make an impact trade, or trust that production will even out if the hitters already in-house are given time?

Injuries haven’t helped; the Brewers had as many as 19 players on the injured list at one point in late April and early May, and their absences have included some of their most counted-upon hitters, like Christian Yelich, Lorenzo Cain, Omar Narváez and Kolten Wong. Tuesday marked the first time since the second week of April that all four of those players were active at the same time, so the Brewers hope to finally see what kind of team they really have. -- Adam McCalvy

Cardinals: What, exactly, is the biggest need?

The Cardinals will be buyers at the Trade Deadline. There's no question about that. But what will they be targeting? The outfield offense was a question mark entering the season, but Tyler O'Neill, Harrison Bader and Dylan Carlson have shown to be a capable trio when healthy -- which has been the biggest problem. O'Neill was proving a power punch in the middle of the lineup before landing on the shelf, so if Bader -- and now Justin Williams, too -- doesn't continue to prove capable at the plate, this could be a midseason upgrade target.

But maybe it's not. Maybe the club hones in on its rotation, bolstering a group that's set to welcome back Miles Mikolas soon for the first time since the 2019 season. Someone like John Gant has filled in capably, but if the Cardinals want to provide some insurance or another ace atop the staff alongside Jack Flaherty, there have been rumblings of hometown kid Max Scherzer's availability should the Nationals fall out of the race. Or maybe it's the bullpen that needs a facelift, with a sky-high walk rate in the early goings.

There's zero question where the Cardinals see themselves come July 31. Now it's more of a question of where their exact desires lie. -- Zachary Silver

Cubs: Should they stay or should they go?

A little more than a quarter of the way through this season, the Cubs are still trying to determine what kind of team they have this year. A rough April has been followed by an encouraging May, but that has left the North Siders dancing around a .500 record and uncertain footing in the potential postseason picture. By the All-Star break, the Cubs' decision-makers will need to have a better sense of how to approach the Trade Deadline in what is without question a critical year in the franchise's timeline.

Rightly so, there is a lot of focus on the core trio of Kris Bryant, Javier Báez and Anthony Rizzo, who can each become a free agent next winter. Bryant has been playing at an MVP-caliber level, while both Báez and Rizzo have been warming up in the batter's box in recent weeks. The question of contract extensions lingers for the three crucial parts of the Cubs' past and present.

That said, there are more than a dozen players on Chicago's roster who could reach the open market (including those with options for 2022). Among the others are closer Craig Kimbrel, pitchers Jake Arrieta and Zach Davies, and outfielders Joc Pederson and Jake Marisnick, among others. By the Deadline, the Cubs will need to know if they are looking to add to a roster with a realistic shot at contending down the stretch, or if all the potential free agents could net some promising prospect return with the team's long-term vision in mind. -- Jordan Bastian

Pirates: Who is here to stay?

The Pirates have had stretches where they’ve exceeded expectations this season, even with mounting injuries that have kept players like Ke'Bryan Hayes, Steven Brault, Colin Moran and Chad Kuhl off the field. However, this team is far from playoff contention and will be sellers at the Deadline this season. The question is: Who do they trade, and who do they build around?

The good news is many of the clear candidates for this season or next are performing well in 2021. Adam Frazier leads the NL in hits, and with middle-infield prospects like Nick Gonzales, Ji-Hwan Bae and Liover Peguero in the Minors, his high value plus the Pirates’ Minor League depth could warrant a good trade. Richard Rodríguez could be one of the eighth- or ninth-inning shutdown guys who teams give up a good prospect for to go for a title. Is the timing right this go-around?

But what about players like Kuhl and Moran, who are on team-friendly deals and likely won’t net the hauls that Frazier and Rodríguez will? Could the Pirates find a suitor for Gregory Polanco, who has had more slumps than streaks? Will there be a surprising deal in the mix? -- Jake Crouse

Reds: What to do at shortstop?

So far, the attempt to move Eugenio Suárez from third base back to his original position of shortstop has not worked well. Suárez ranks near the bottom of the Majors, according to FanGraphs, in defensive runs saved (-6) and defensive WAR. He’s also already made seven errors in 30 games played at the position . It’s possibly affected him offensively, as he is also ranked near the bottom of baseball in hitting among qualified batters. If manager David Bell and the club ends the experiment, it could hurt the confidence of the usually upbeat Suárez even more. Plus, Mike Moustakas has been a solid third baseman, and there are no other clear options at shortstop. At the moment, the only clear option is to hope Suárez gets comfortable with both sides of his game and can find his way out of the rut. -- Mark Sheldon