Taking Berkman's place on the roster will be Skip Schumaker, who is wrapping up his Minor League rehab work with Triple-A Memphis on Thursday. Schumaker will join the club on Friday in Pittsburgh, where the Cardinals begin a six-game, two-city road swing.
Berkman reported feeling "still pretty sore" on Thursday morning, a day after a misstep during his pursuit of a popup caused a recurrence of tightness in his calf. Berkman exited that game early and spoke afterward about the possibility of needing a DL stint in order to ensure that he can move on without compromised health.
The same injury sidelined Berkman for three weeks in 2009.
Mozeliak added that it would be more challenging to carry an unavailable Berkman on the roster -- as the team did last week -- right now, given that the club doesn't have another off-day until April 26. Berkman missed four games from the initial calf strain before returning to the lineup on Tuesday.
Berkman's injury prompted the Cardinals to revisit Schumaker's rehab timetable. Just two days ago, manager Mike Matheny said that a weekend return would "probably be too early" for Schumaker, who has been out with a right oblique strain since mid-March.
There was also precedent for keeping conservative with Schumaker's track. Before joining Memphis on Sunday, Schumaker noted that he did not want to repeat last year's issue of rushing through a rehab assignment and then coming back at less than 100 percent.
Sharing the same concern, Mozeliak spoke with Schumaker before changing course. Schumaker told Mozeliak that he feels ready.
"When you look at where he's at -- and we checked with him -- we can be careful without being overly demanding with what his role will be when he first comes back," Mozeliak said. "We felt like this was the safest move to do."
Thursday's game was Schumaker's fourth game with Memphis. He made his second start at second base and was slated to play a full nine innings for the first time. Schumaker's other two appearances came in the outfield, and he began the day with three hits in his first 10 at-bats.
The Cardinals did consider calling up Triple-A first baseman Matt Adams, but with Matt Carpenter off to such a hot start, the team was not likely to have enough playing time to warrant Adams' addition. St. Louis plans to use Carpenter as the team's starting first baseman during Berkman's absence.
Carpenter entered Thursday with 11 RBIs and nine hits in 24 at-bats.
"Right now, with the way he's playing, give him a shot," Mozeliak said.