However, the slugger and manager Tony La Russa both downplayed the condition, and Pujols expects to start Sunday's Game 2 at 7:30 p.m. CT on TBS at Citizens Bank Park.
Pujols didn't appear to be moving very well for much of the game. After he singled in the ninth inning, he was removed for pinch-runner Gerald Laird.
"His heel was barking," La Russa said. "There was no reason at that point. We keep scoring and his [spot] comes up. I wish it wouldn't have, but his heel was barking, and he didn't want to run the bases in the ninth. He'll play tomorrow."
Pujols said even less about the situation than La Russa did.
"I rolled my ankle a little bit in Houston, but it was fine," Pujols said.
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.