"We need to call up somebody that fits in to the most needs that one guy can fit in," La Russa said, "and deserves a promotion."
The move will provide some insight, meanwhile, as to how the Cardinals plan to proceed at first base. They have a ready option in Lance Berkman, who was a capable if not dazzling first baseman as recently as 2009. Moving Berkman from right field would open up at-bats for Jon Jay, and eventually for Allen Craig -- though Craig is not expected to return from a broken kneecap for another three to four weeks. However, it may not be the course the Cardinals take.
That's because they're not sure the best thing for Berkman's health is to play first. Berkman was something of a health question coming into the year, but he has held up very well so far while playing right field almost exclusively.
"When we were talking to him after he signed him and people were worrying about his legs in the outfield, he said actually first base is more stressful with the quick lefts and rights," La Russa said. "So getting Lance in a place where he's physically feeling the best is a real good answer for us -- and can play the most."
If the Cardinals decide to make Berkman their primary first baseman while Pujols is out, they likely will not call up Hamilton. If Hamilton is recalled, it is probably an indication that Berkman will continue to see a lot of time in the outfield.
Other candidates on the 40-man roster include infielder Matt Carpenter and outfielder Adron Chambers. The Cardinals' 40-man roster is full, so it would be difficult to bring in a player not currently on that list. Andrew Brown, who's currently on the active roster, could see some time at first as well.
Then there's the lineup, which also is something of an unknown. Matt Holliday seems like the most likely candidate to bat in Pujols' customary third spot, with Berkman batting cleanup. But on days when the Cardinals have a right-handed hitter in the No. 2 spot, they might go with Berkman third and Holliday fourth.
As for roster concerns beyond first base and the No. 3 spot in the batting order, they'll be magnified. In a close division race, there's little margin for error. So the Cardinals may be more aggressive in looking to upgrade other places on the club between now and the non-waiver Trade Deadline on July 31.
"That's obviously something you think about," Mozeliak said. "But I don't think we're in a position yet to really determine if we go down that path. But one of the things we were trying to do was make sure we scored runs this year. Losing your No. 3 hitter isn't going to help. But we've had creative ways of scoring runs, and we'll just see. But does it open some potential opportunities out there that maybe you wouldn't have explored 48 hours ago? Yeah."
Then again, just about everything has changed for the Cardinals in the last 48 hours or so. And for Pujols as well. The injury has also clouded what was the biggest issue for player and club back in February: Pujols' status for 2012 and beyond.
He is eligible for free agency following the season. Pujols was already putting up somewhat less than his usual numbers, though he had come on in a big way lately. But the injury will obviously knock down his overall stats at the end of the year, and a wrist injury is different from, say, a knee or ankle injury. If Pujols doesn't come back at full effectiveness, there will be some question as to what to expect from him next year.
That doesn't necessarily mean the team's chances of re-signing its signature player will go up, of course. It just means that the whole situation has gotten a good deal more complicated.