Pujols was hurt in a collision at first base with the Royals' Wilson Betemit. He is also experiencing some soreness in his left shoulder, but the wrist injury is the greater concern at this point.
"I can't give you too much until we do X-rays tomorrow," Pujols told reporters after the game. "Pretty much right now, I'm just telling you I'm pretty sore in my wrist and my shoulder. We'll see tomorrow. We took a look at it. I passed a couple tests. But tomorrow, we still need to do an X-ray and an MRI. They can't tell anything with the machine that we have here."
General manager John Mozeliak said on Sunday afternoon that Pujols underwent an X-ray as part of his initial examination, and that no broken bones were revealed at that time. Still, a full read on the severity of Pujols' injury will not be available until at least Monday.
"There is going to be another round of diagnostic testing in the morning," Mozeliak said. "Just to rule out ligament issues and all that. I'm cautiously optimistic, but I couldn't handicap it either way at this point."
Mozeliak and manager Tony La Russa both declined to say whether they expected Pujols to require a disabled-list stint.
Leading off the sixth inning, Wilson Betemit hit a slow roller up the middle. Pete Kozma fielded the ball and made a throw to Pujols, and as Betemit got to first base, he made contact with the slugger's left arm. That knocked the mitt off of Pujols, and Pujols hit the ground in obvious pain.
"Basically, he ran the mitt into me," Betemit said. "I didn't know where he was going. I was running hard and the ball got there at the same time I got to the base. I couldn't do anything. It just happened."
Head athletic trainer Greg Hauck examined Pujols on the field, and Pujols was removed from the game. Lance Berkman took over for him at first base. Pujols had put the Cards ahead in the previous half-inning with a solo homer off Royals reliever Louis Coleman.
"When I come out of the game, believe me, something is really wrong," Pujols said. "I knew I wouldn't be able to be in the game, and I think that's a smart move to make."
The Cardinals have had a staggering run of injuries already in 2011. They have used the disabled list 13 times and have seven players currently on the DL, including two with hand or wrist injuries.
Still, Pujols holds out hope that he will avoid being the 14th Redbird to be shelved.
"Nobody wants to be on the DL," he said. "As an athlete, that's something that you want to avoid. Can you control that? No. but that's something that you want to avoid, the DL. So I don't even want to talk about that. Talking about the DL is talking about negative, and I'm a guy, I'm really positive no matter what kind of situation I'm in."
Matthew Leach is a reporter for MLB.com. Read his blog, Obviously, You're Not a Golfer and follow him on Twitter at @MatthewHLeach. This story was not subject to the approval of Major League Baseball or its clubs.