In just under three weeks, baseball will return to Busch Stadium. Slowly but surely, the St. Louis Cardinals are piecing together which 26 players will be named to their Opening Day roster.

Some decisions are pretty easy. Others, not so much.

Eighteen spring training games remain on the docket, and president of baseball operations John Mozeliak and manager Oli Marmol will need all of them to decide what the active roster will be when the Cardinals officially kick off their “transition” season.

We’ve broken down the most intriguing remaining names in camp and placed them into three tiers: Who’s in, who’s probably in and who we’re watching. Let’s take a look at how things are shaping up.

Tier 1: The locks

No real surprises. St. Louis caught a break with Walker, who aggravated his left knee on a sprinkler head cover in right field during Tuesday’s split-squad game. Imaging showed no structural damage, though the Cardinals will give Walker a week of rest to let some inflammation subside. He is expected to ramp back into games shortly after and should not see any setbacks relative to an Opening Day timeline.

The Cardinals are still configuring how best to use Gorman, but it’s a safe bet he’ll split time between second base and as a roving designated hitter. Though Marmol would prefer to keep some sort of position consistency this year, the DH spot is an area he could utilize to maximize playing time for as many players as possible.

Gorman can also play third base on the rare occasions when Arenado has an off day. Donovan will resume his super-utility role for another season, though he remains a stronger infielder than outfielder (and the outfield is crowded enough already). Nootbaar can play either corner outfield spot, but with Walker set for most of the reps in right field, he’s looking at a majority of his playing time coming in left. Of course, the Cardinals could also decide to go with an offense-first approach and put Nootbaar in center field, which would shift Donovan to left field. Clearly, there is still some work to do regarding the outfield picture. Expect a decision to go down to the wire.

From a pitching standpoint, the Cardinals are relying on their veteran starters to keep them afloat in April. They have not yet tabbed an Opening Day starter, but it’s not exactly brain surgery to expect Gray to have that honor. St. Louis is also trying to restructure its bullpen, a pivotal (and arguably most valuable) area of last year’s roster. The Cardinals need a setup man from both sides to back up Helsley. Romero will get the nod from the left side based on his performance there last season. Fernandez is the early candidate from the right side.

Tier 2: The most-likely’s

The question surrounding Burleson isn’t if he’ll play, it’s where. With Gorman slated for the majority of the at-bats (at least to start the season), Burleson will likely see most of his time as a bench bat or designated hitter when Gorman is at second base. This situation remains fluid, and it is fair to question whether the Cardinals can justify sitting one of their top contact hitters against right-handed pitching last year. Herrera and Pagés will be on the Opening Day roster, but their playing time is still being determined.

Matz has looked healthy throughout spring. As he stretches out over the remaining weeks, the organization will get a better sense of how effective he will be (though the early returns have been encouraging). What the club must weigh is what is best short-term versus long-term. The Cardinals seem inclined to use Matz in the rotation to start the season, but that is not a guarantee — especially if Andre Pallante and Michael McGreevy continue their strong spring campaigns. Barring a late-spring trade (which is unlikely but not impossible), Matz will be on the roster, presumably as a starter.

Liberatore has been dominant all spring. He has retired 21 of the 22 batters he’s faced and has not given up a hit. Team brass is still contemplating whether to use him as a multi-inning reliever (a role he thrived in last year) or as starting pitching depth. All inclinations point to the former, but nothing is finalized. King has been a staple in the bullpen since being traded to St. Louis in 2023, and that shouldn’t change, though the final decision will depend on where Matz and Liberatore start the year.

Tier 3: The big questions

As advertised before spring, the most critical question for the Cardinals is center field. Siani had the majority of reps there last year, and he’s proven a standout defensive player. But Scott has had an impressive spring. Coming into Thursday’s game, he was 7-for-12 with a double, triple and a home run, and his elite speed continues to play. The decision between the two would have been tough enough as is, but Nootbaar potentially seeing time in center has complicated things even more. That’s why Scott has seen time in left field; Marmol wants to maximize playing time for all three players in what will be a difficult decision all around. There is no front-runner for the starting role.

The same can be said for the final spot in the rotation. Assuming Matz is tabbed as a starter, what does that mean for Pallante and McGreevy? Pallante had a standout second-half performance last year and came in as a lock for a starting role. But McGreevy has been excellent, with two scoreless outings and just one hit allowed. The Cardinals want to see McGreevy as much as possible this year, and there has been some talk of him starting the season in the bullpen. But that raises two questions: How McGreevy can continue establishing himself as a starter and whether that is best for the club long-term as it tries to configure plans for 2026 and beyond.

Baker could slug himself onto the roster. His three homers lead the team this spring. Baker is limited defensively but could serve as a power bat off the bench from the right side, a role the Cardinals lacked last year. That leaves one of the various utility options to fill the final spot (and is why Barrero, Fermín and Helman have all spent time in the outfield lately). The advantage here will likely go to a player who can play shortstop. St. Louis does not have a true backup shortstop behind Winn. This would presumably give Barrero or Helman the upper hand, but nothing is for certain.

The final spots in the bullpen are anyone’s guess. Graceffo leads this group with the highest percentage of making the roster. Roycroft and O’Brien had experience in the bullpen last year. Muñoz was claimed off waivers as a starting pitcher, but the Cardinals view him as more of a high-upside reliever.