JUPITER, Fla. — One week of Grapefruit League action remains for the St. Louis Cardinals, who are starting to see their Opening Day roster take form.

A few questions remain — the final spot in the rotation, a couple of relief roles, and the starting center-field job — but president of baseball operations John Mozeliak and manager Oli Marmol have at least established the backbone of this year’s club. All signs point to the Cardinals utilizing a traditional 26-man roster, meaning 13 position players, five starting pitchers and eight relievers.

The first version of The Athletic’sroster projection focused on multiple areas of the roster that were then considered wide open. After a series of cuts, the position battles are much more defined. In our second version, we’ll take our best guess at the 26 players we expect to see at Busch Stadium come March 27 and explain the team’s current thought process behind each decision.

This especially applies to center field. You have been warned.

Infielders (5) — Nolan Arenado, Willson Contreras, Brendan Donovan, Nolan Gorman, Masyn Winn

Arenado and Contreras are set at their respective corners and the middle of the lineup. Winn is set at shortstop. Gorman and Donovan will be in the everyday lineup, but where they play will depend on the day.

Marmol will switch between Donovan at second base and Gorman as the designated hitter while working in consistent at-bats for Alec Burleson. He’ll also be tasked with balancing a turnstile of left-handed bats, with the front office prioritizing Gorman’s playing time. Some versions of the lineup (specifically against right-handed pitching) will see Gorman at second base, Burleson as the DH and Donovan in left field.

Catchers (2) — Iván Herrera, Pedro Pagés

This tandem has been known since November. The Cardinals haven’t announced who their starting catcher will be, though they could easily platoon the position. There might be an organizational preference to start Herrera based on offense — he hit .301 with an .800 OPS in 72 games last year — and his right-handed bat would help balance out a lefty-heavy roster. But Pagés has the upper hand defensively, as Herrera’s issues controlling the run game haven’t looked much better this spring. Either way, expect to see both young catchers plenty to start the year.

Outfielders (3) — Lars Nootbaar, Michael Siani, Jordan Walker

And here comes the angry mob. Let’s discuss the corners first: Nootbaar and Walker should be locks for the corners, as the Cardinals will prioritize their everyday at-bats. Walker missed over a week of games with left knee inflammation but returned to Grapefruit League action on Saturday, going 0-for-2 with a walk over six innings.

But the true competition this spring has always been center field. Scott and Siani have similar profiles: They are both left-handed, defense-first players with top speed, though Siani is the better outfielder according to metrics. Because of their similarities, the Cardinals won’t consider carrying both players; one will start in St. Louis, and one will start in Triple A. If this camp were strictly about performance, this would be Scott’s job by a mile. He has outperformed Siani offensively: Scott is 10-for-29 (.345) with a 1.009 OPS, while Siani has tallied just two hits total over 33 at-bats. Still, the club is in gridlock over who should start come Opening Day.

The Cardinals aren’t just weighing performance. They’re also weighing what is best for each player in the long term. St. Louis will play Nootbaar in center field in some games this season. Though Scott and Siani are much better defensive center fielders, Nootbaar in center is the only lineup configuration that ensures the at-bats needed for Gorman, Donovan and Burleson. This means the club is looking at center field being somewhat of a platoon position to start the year.

The team is weighing what’s best for Scott. The Cardinals are comfortable sitting Siani or utilizing him as a late-inning defensive replacement. They are not as comfortable doing that with Scott, who they believe needs to play every day to maximize his development.

The Cardinals are not close to deciding between the two, with multiple people in the organization referring to the decision as “very tough.” It’s still a coin flip. It would be difficult to justify starting Scott in Triple A if Siani’s offensive production does not progress. But if development takes precedence in this transition season, it would also be hard to explain Scott sitting on the bench in the majors.

Bench (3) — Luken Baker, Jose Barrero, Alec Burleson

As discussed above, Burleson won’t be used solely as the team’s left-handed bench bat. He still will be considered an everyday player and will start some games. But there is value in having Burleson in pinch-hit situations based on his high contact rate.

Baker has slugged himself onto the roster. The Cardinals lacked a power-hitting right-handed bat last year, and it cost them in countless late-inning scenarios. Given the club’s emphasis on offense this year, having someone such as Baker specifically serve as an option off the bench would be a boost.

St. Louis does not view Baker as someone who needs to play every day. Instead, the club is developing him into a full-time bench bat. A clear sign as to how the Cardinals view Baker: Over the last week, he has taken reps in the backfields during the first few innings of games. Marmol has then used him as a pinch hitter in later innings in potential run-scoring scenarios. This is designed to mimic the game situations where Baker is set to see the most usage during the regular season.

With Baker and Burleson providing power and contact, the Cardinals could lean to defense to round out their bench. It’s a toss-up whether they go Barrero or Fermín, utility players who can hop around the diamond and can play as a backup shortstop when needed (outside of Winn, the Cardinals do not have a true shortstop on the 40-man roster).

Barrero has a slight upper hand because of his ability to play center field. While Fermín will probably post better quality at-bats in terms of contact rate, Barrero’s athleticism gives him the edge defensively. Koperniak will likely start the year in Memphis, providing outfield depth — another area the Cardinals need.

The drawback with Barrero is that he would require a 40-man roster spot. However, depending on the severity of Thompson’s injury (lat strain), he could be a 60-day injured list candidate, which would free up a spot for Barrero without losing another player.

Koperniak has hit well this spring, but the Cardinals already will have at least five left-handed hitters (Burleson, Donovan, Gorman, Nootbaar and either Scott or Siani) on the roster. From a roster construction standpoint, mixing in Koperniak would further complicate an already tricky puzzle.

Rotation (5) — Erick Fedde, Sonny Gray, Steven Matz, Miles Mikolas, Andre Pallante

Matthew Liberatore is still in the mix for a starter spot, with Mozeliak saying earlier in the week that Liberatore would begin the season in St. Louis regardless of role. While the club is leaning towards placing Liberatore back in the bullpen, where he thrived as a multi-inning reliever (Liberatore posted a 3.61 ERA over 63 1/3 innings in relief last year), no formal decision has been made. But if Matz continues to look strong, the likelihood is that he will round out the rotation, which would slot Liberatore to the bullpen.

Gray and Fedde have not looked sharp, but pitchers have different routines and preferences for building up over the spring. Gray, for example, said after his last start that he was not yet throwing full strength and was still working through the feel of multiple pitches. He and Fedde will have at least two more exhibition starts. The Cardinals expect to name their Opening Day starting pitcher by Sunday. It would be quite surprising if that is not Gray.

McGreevy looks to be the odd man out despite a stellar spring showing (two earned runs over 10 2/3 innings so far). There is a valid argument to make for him breaking camp in the big-league rotation, however, the Cardinals are trying to protect what is left of their rotation depth. With Zack Thompson and Drew Rom on the injured list, the organization is not comfortable with its slim options in Triple-A Memphis. St. Louis also will not rush up its top pitching prospects — Quinn Mathews, Tink Hence and Tekoah Roby — simply for the sake of need. That results in a tough break for McGreevy, who will certainly be the first man up when an injury occurs.

Bullpen (8) — Ryan Fernandez, Ryan Helsley, John King, Kyle Leahy, Matthew Liberatore, Phil Maton, JoJo Romero, Chris Roycroft

A flurry of roster moves helped solidify what had become a competitive part of the roster. The Cardinals signed veteran right-hander Phil Maton to a one-year, $2 million contract Thursday, adding depth and experience to an otherwise young bullpen. St. Louis also optioned Gordon Graceffo, Roddery Muñoz and Riley O’Brien to Memphis over the week. Graceffo will stretch back out to a starter’s workload in Triple A, where he’ll look to bulk up the aforementioned rotation depth.

The majority of last year’s relievers will return to their same roles. Helsley will close, and Romero will be used as a set-up man from the left side. Fernandez will have chances in high leverage from the right side. Though Maton signed just a few days ago, he said his arm is “completely built up.”

The Cardinals are comfortable ramping him up quickly and believe he will be ready for Opening Day. If that is the case, expect the durable Maton — who has appeared in at least 65 games in each of the last four seasons — to be used similarly to how Andrew Kittredge was last year.

Roycroft, Leahy and Nick Anderson will compete for the final two spots. From a competitive standpoint, Leahy and Roycroft have the advantage. Anderson, a non-roster invite, has not performed nearly as well as either pitcher this spring and his current roster status would require a corresponding move. However, Anderson’s contract includes an upward mobility clause, meaning he can negotiate with other teams should a spot on their major-league rosters open. The Cardinals might be inclined to keep him for the sake of protection — and their bullpen will be fluid as seven of the nine listed relievers have at least one option remaining. Still, Leahy and Roycroft should get the nod, giving the Cardinals five righties and three lefties in the bullpen.