Good outfield defense is crucial in an era of heavy fly-ball contact, and the National League Central is home to some great fielders -- and great hitters -- in its outfield ranks.

Some of the trios seem more set in stone, as is the case for the defensively sound Cardinals. For others, like the Pirates, there are still position battles to be played out this spring. And the Cubs are home to a new everyday outfielder in Joc Pederson, though there are some questions about him as well.

Here’s a look at what we know and what we’re eager to learn about the outfield mix for NL Central clubs.

BREWERS

The known: While they have question marks dotting the infield and the pitching staff, the Brewers were set in the outfield as Spring Training got underway. They have Christian Yelich in left field, Lorenzo Cain in center and Avisaíl García back in right with the return of Cain, who elected not to play in 2020. It’s a strong group, provided Yelich returns to his 2018-19 form after falling into the same small-sample trap that caught a number of baseball’s best hitters during the shortened 2020 season. The Brewers are betting he will. They are also buoyed by the return of Cain, who, coupled with the addition of Gold Glove Award-winning second baseman Kolten Wong, solidifies the up-the-middle defense.

The unknown: How long will it take Cain to return to form after sitting out the bulk of last season? Brewers manager Craig Counsell is cognizant that it will take some time, and the Brewers will attempt to strike a careful balance in Spring Training of getting Cain additional at-bats without wearing him out. The other question marks are about the outfield corps beyond the current starting trio. The Brewers have brought in Billy McKinney, Derek Fisher and Tim Lopes by combination of a waiver claim and trade, joining incumbents on the 40-man roster in Tyrone Taylor and Corey Ray, who is the team's No. 10-ranked prospect, per MLB Pipeline. This is potentially a big year for Ray, who has not yet performed to the level the Brewers hoped when they made him the fifth overall pick in the 2016 Draft. -- Adam McCalvy

CARDINALS

The known: The candidates, at least. Tyler O’Neill, Harrison Bader and Dylan Carlson are projected to start for the Cards -- from left to right, in that order -- with Lane Thomas, Justin Williams and Austin Dean expected to push, if not compete, for a job. Their defense will also be unquestioned, with O’Neill a Gold Glove Award winner in 2020, Bader a finalist in ’19 and an Outs Above Average savant and Carlson capable of playing any of the three spots. There’s open competition here at Spring Training -- one the Cardinals welcome and are eager to see unfold.

The unknown: Essentially everything else. How will the bats play? With Bader the eldest of the likely starters at just 26, is that a sustainable makeup? Can Williams, or especially Thomas, force their way in? Save for the back end of the rotation, the outfield is the Cards’ biggest question mark heading into 2021. Only Bader has more than 100 career starts, and all three have yet to take off with the bat at the Major League level. There’s unmistakable confidence that Carlson, the club’s switch-hitting No. 1 prospect, can be a middle-of-the-lineup threat; it just remains to be seen when that comes to fruition. -- Zach Silver

CUBS

The known: Arguably the biggest development for the Cubs on the offensive side in 2020 was Ian Happ earning the trust of manager David Ross as the everyday center fielder and leadoff man. Happ will reprise both roles this season, and he returns as Chicago’s WAR leader (1.9, per FanGraphs) from last season. Veteran Jason Heyward, who enjoyed a solid showing last year (1.8 fWAR), will be in right field, providing his Gold Glove-caliber defense. The Cubs added slugger Joc Pederson over the offseason to play left, and center fielder Jake Marisnick joined the fold as a complementary piece who can help against lefties and enhance the defense late in games.

The unknown: Pederson signed with the Cubs after the North Siders parted ways with slugger Kyle Schwarber. Pederson and Schwarber have similar offensive profiles, though the former has a stronger history against facing upper-zone fastballs, and he is an upgrade defensively. That said, the Cubs plan on starting off with Pederson as a full-time player and not a platoon option. For his career, Pederson has a 59 wRC+ against lefties, so there is risk in that approach by Chicago. The Cubs also will need to see if what Happ did in the short-sample 2020 was actually a sign of things to come. Beyond that, the Cubs will be weighing its bench depth. Marisnick is an expected part of the Opening Day roster. Veteran Cameron Maybin is also in camp as a non-roster invitee, competing for a job. -- Jordan Bastian

PIRATES

The known: Pirates manager Derek Shelton said Gregory Polanco will play right field and Bryan Reynolds will play some combination of left and center, but he’s expected to get most reps in left. That’s because two speedy options with center-field experience -- Anthony Alford and Brian Goodwin -- will compete for time there, as well as Jared Oliva, the Pirates’ No. 12 prospect who is seen as a potential center fielder of the future for the team. Troy Stokes Jr., whom the Pirates claimed off waivers from the Tigers, is knocking on the door of the Majors as well.

The unknown: How will Alford bounce back from the right elbow fracture he sustained on Sept. 6? Alford has a good chance to be the Opening Day starter in center field if he’s healthy, as the Pirates want to see what he can do with consistent reps unlike what he saw in Toronto. Goodwin, who is the other option for Opening Day, is in the fold if things don’t go well, but can Goodwin shake off his slow end to the 2020 season, when he went 8-for-49 (.163) after being traded to the Reds? -- Jake Crouse

REDS

The known: Once again, the Reds sure do have a lot of outfield depth with Nick Castellanos, Jesse Winker, Nick Senzel, Shogo Akiyama and Aristides Aquino. The one spot to count on regularly will be Castellanos manning right field, and he will be seeking to rebound from a subpar first season in Cincinnati. His OPS+ plummeted from 153 in 2019 to 102 in ’20, while he batted .225/.298/.486 with 14 homers. Castellanos was a defensive liability, which will also be a focus for improvement.

The unknown: With no designated hitter in the NL, it’s unclear how manager David Bell will allocate playing time to the remaining outfielders. The right-handed-hitting Senzel has missed extensive time the past two seasons with health issues, but he is coming into camp healthy. The lefty-hitting Akiyama made only one start vs. left-handed pitching last season. Another lefty hitter, Winker had a career-best 142 OPS+, but he was primarily the DH. Aquino, a righty who was a home run-hitting sensation as a 2019 rookie, spent most of ’20 at the alternate training site until getting some chances later on. If the Reds decide that they need a more experienced shortstop, they could perhaps tap into their outfield depth to make a trade. -- Mark Sheldon