Pujols, last year's NL MVP and this season's major league leader in home runs and RBI, was placed on the 15-day disabled list Sunday.
"Life would be easier with Albert," closer Jason Isringhausen said. "But we've played without our star players before. We'll have to weather the storm."
On Sunday, Pujols told ESPN's Harold Reynolds that the Cardinals' medical staff told him that the injury might not keep him out past the 15 days that he is on the DL. On Saturday, Dr. George Paletta, the team's orthopedic consultant said that Pujols could be out as long as six weeks.
Pujols also told Reynolds he was up and around and feeling better.
Last year, the Cardinals soldiered through Scott Rolen's two shoulder operations, Reggie Sanders' broken leg and Yadier Molina's broken hand, injuries that did not prevent them from their second straight 100-win season.
An MRI exam scheduled for Monday will give the team a better picture how long Pujols, batting .308 with 25 homers and 65 RBI, will be sidelined.
On Sunday, trainer Barry Weinberg characterized the injury as "moderate to severe," saying it was closer to severe than moderate, and said Pujols had limited mobility and pain.
"Now, we just go through the steps of getting him better," Weinberg said. "The first thing he has to do is normal things: coughing, sneezing and opening the door.
"Then we can get more aggressive with the rehab and we can get more aggressive with some baseball activity."
Manager Tony La Russa said Pujols heard something pop when he tried to chase Aramis Ramirez's foul pop fly in the second inning on Saturday, then pulled up and grabbed his right side. Pujols finished the inning but was removed before the third inning.
"He doesn't give into pain very much," La Russa said. "So I knew there was something going on."
Weinberg said it was a positive sign that Pujols was injured in the field rather than swinging.
Jim Edmonds, nursing an abdominal injury that sidelined him for a week and threatened to land him on the DL, too, played first base Sunday against the Chicago Cubs after taking ground balls at the position a few hours before the game. Edmonds was 3-for-3 with two RBI, helping the Cardinals win 9-6.
Edmonds, an eight-time Gold Glove center fielder, has been unable to run since being injured. But La Russa noted that he can swing a bat, and said Edmonds would not worsen his injury by playing.
"It's not rocket science here," Edmonds said. "The first baseman got hurt and we're short some guys. I figured if I can go out there and play for a couple of days and get a little bit better as I'm playing, it will be better for us. But if it's not, it's not."
La Russa said he's been told by team medical personnel that Edmonds cannot worsen the injury by playing.
"He's going to have some pain and he may get more pain from playing," La Russa said. "If it gets too painful to where he can't function, he doesn't play, but the injury will not be aggravated."
Rolen moved into Pujols' third slot in the lineup, and La Russa said Rolen most likely would bat third the majority of the time Pujols is out.
"You're not going to replace Albert Pujols," Rolen said. "You can search through the league for his replacement."
"It just goes to show you it's a long season, No. 1," he said. "No. 2, it's a test of really who has the most depth."
Baker said losing Pujols or Lee was a good comparison. The Cubs were 12-27 since Lee was hurt on April 21.
"There's a direct correlation," Baker said. "Big-time."
Now comes the Cardinals' turn to deal with adversity.
"It's part of grinding through a season, it's just something you've got to deal with," La Russa said. "The guys that have a chance to play can make a contribution, and if they do, you get by with it."
On the plus side, Chris Carpenter is to come off the disabled list from bursitis in his back Tuesday and start against the Reds. Carpenter won 21 games and the NL Cy Young Award last year.
Rookie Chris Duncan was recalled from Triple-A Memphis in time for Sunday's game against the Chicago Cubs. Duncan, beginning his second stint with the team this season, was batting .272 in 42 games with six homers and 25 RBI.
Duncan, the son of pitching coach Dave Duncan, appeared in four games earlier in the season and was 1-for-5 with a homer and three RBI. Duncan had a pinch infield hit in the sixth Sunday.
Information from The Associated Press was used in this report.