MINNEAPOLIS -- Though third baseman Josh Donaldson was the crown jewel of the Twins' busy offseason, the 2015 American League MVP Award winner will not be on the field for the first round of the '20 playoffs, as he couldn't fully push his right calf in his on-field workouts on Monday after suffering cramps in the area on Friday.

Donaldson was able to take swings in batting practice, but he felt limited during his subsequent mobility drills down the first-base line, and the Twins didn't want to push him back into action and expose him to the potential for further injury. He missed a month with a right calf strain earlier this season and has a history of injuries to both calves.

The only question was whether Donaldson would be available on the roster as a pinch-hitter. Ultimately, the Twins decided to maintain their roster flexibility and emphasize his health.

"At this point, we weren¡¯t going to be able to play him at third yet," Twins manager Rocco Baldelli said. "We weren¡¯t going to be able to let him run the bases for himself yet. So, it was, ¡®Are we going to use him once a game to take an important at-bat for us?¡¯ And watching him also move, not wanting to take the chance that he takes a swing and comes out of the box even at 75 percent, we could not take that risk that something was going to happen and set him back."

Though that was tough injury news for the Twins on Tuesday morning, the 28-man active roster for the AL Wild Card Series against the Astros did feature center fielder Byron Buxton, who recovered from his head contusion and mild concussion symptoms enough to start Game 1 and bat second for his second career postseason game.

It's an unprecedented roster befitting of the unprecedented circumstances.

With Donaldson down, the Twins added Willians Astudillo as a fourth catcher and surplus infield depth for the three-game series. And in one of the most anticipated moves of all, outfielder/first baseman Alex Kirilloff, the No. 2 prospect in the organization and No. 27 prospect in baseball, could become the third player in MLB history to make his big league debut in the postseason after he was included as an outfield depth option. But there are two other players who could join Kirilloff to expand this exclusive club. Chas McCormick, the Astros' No. 24 prospect per MLB Pipeline, was included on Houston's roster for the series, while Shane McClanahan, the Rays' No. 6 prospect and the No. 99 prospect in MLB, was included on Tampa Bay's roster for its series vs. Toronto.

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Marwin Gonzalez figures to receive most of the playing time at third base in Donaldson's absence, with Ehire Adrianza and Astudillo backing him up. With Gonzalez locked into the infield and LaMonte Wade Jr. ineligible for inclusion after being optioned on Saturday, Kirilloff will be needed to back up Jake Cave as outfield depth, particularly given Buxton's recent injury uncertainty.

The Twins could take all of those liberties on the position-player side because of the format of the three-game series, which puts less emphasis on pitching depth.

To that extent, Minnesota will only carry 13 pitchers, including starters Jake Odorizzi and Randy Dobnak as depth behind its series rotation of Kenta Maeda, José Berríos and Michael Pineda. Of the Twins' core nine relievers, hard-throwing rookie Jorge Alcala was left off the roster, while Rich Hill was the odd man out in the starting rotation.

"Referring to Jake and Randy to some degree, those guys can get outs in shorter stints, too," president of baseball operations Derek Falvey said. "I mean, this is the playoffs. We¡¯ve seen those guys come in and do some things, and we think they¡¯re two good pitchers. We think they match up well in this group."

Hill was unlikely to factor into this series in any case after he threw 93 pitches in Sunday's regular-season finale. Though Alcala was quite successful this season with a 2.63 ERA and 27 strikeouts in 24 innings, the Astros' familiarity with his arsenal may have played into the decision to leave him off the roster. Alcala was a former Houston farmhand who arrived in Minnesota as part of the 2018 trade that sent Ryan Pressly to the Astros.

Twins' Wild Card Series roster

Pitchers (13): Kenta Maeda, Jos¨¦ Berr¨ªos, Michael Pineda, Jake Odorizzi, Randy Dobnak, Tyler Clippard, Tyler Duffey, Trevor May, Taylor Rogers, Sergio Romo, Cody Stashak, Caleb Thielbar, Matt Wisler

Catchers (4): Ryan Jeffers, Mitch Garver, Alex Avila, Willians Astudillo

Infielders (5): Ehire Adrianza, Luis Arraez, Marwin Gonzalez, Jorge Polanco, Miguel San¨®

Outfielders (5): Byron Buxton, Jake Cave, Max Kepler, Alex Kirilloff, Eddie Rosario

Designated hitter (1): Nelson Cruz