Pujols sprained his left wrist and hurt his shoulder trying to make a tag at first base, but the Cardinals recovered to beat the Royals 5-4 on Skip Schumaker's ninth-inning homer on Sunday.
He will be evaluated on Monday, a day off for St. Louis.
"To be honest, I can't give you guys too much until the X-rays and an MRI tomorrow," said Pujols, whose left wrist was tightly wrapped. "I know I'm pretty sore. Am I worried? Of course. Hopefully, everything will come out negative tomorrow. When I come out of a game, believe me, something is really wrong.
"Hopefully, cross our fingers and I'll be all right."
General manager John Mozeliak said no roster moves are being planned.
"We will know something tomorrow and go from there," Mozeliak said. "Right now, he will be tested in the morning and we'll see."
Manager Tony La Russa said he experienced a range of emotions when he saw his first baseman go down.
"It scared the hell out of all of us," La Russa said. "It smoked him pretty good. The doctor said he has good strength so that makes us kind of optimistic. First indications are that we caught a break."
Wilson Betemit hit a chopper up the middle off starter Jaime Garcia. Second baseman Pete Kozma back-handed the ball and threw while in the air to first, pulling Pujols off the bag. As Pujols went to tag Betemit, he hit Pujols' glove hand and the Cards' three-time MVP went down to the ground in pain.
"He hit me on my wrist and my shoulder," Pujols said. "He kind of jammed me back. It's the toughest play to make as a first baseman. It's a bang-bang play. I saw the replay a couple of times, but I didn't really want to look at it."
The collision was unavoidable, Betemit said.
"I was running hard and the ball arrived at the same time I got to the base," Betemit said. "I couldn't do anything about it. He hit me on my left arm, that's why he dropped the ball. I hit him and then I saw him on the ground. That's part of the game. I couldn't do anything about it."
Lance Berkman, who had been given the day off, replaced Pujols at first.
Pujols, hitting .279 this year, was 3 for 3 with a home run -- his 17th. The fifth-inning homer gave St. Louis a 3-2 lead.
Information from The Associated Press contributed to this report.