Young was taken to Scripps Green Hospital in nearby Torrey Pines with a nasal fracture and a laceration on his nose.
Young sat on the ground for several minutes while being attended to by the team training staff and was able to walk off the field on his own, though he was accompanied by teammate Tony Clark and trainer Todd Hutcheson.
Young opened the inning by retiring Brendan Ryan before allowing consecutive singles to Skip Schumaker and Aaron Miles. Pujols then lined an 0-2 slider up the middle as the ball hit Young flush.
At the time of the injury at PETCO Park, the Padres were leading the Cardinals 2-0 after a two-run home run by Adrian Gonzalez in the first inning.
Catcher Josh Bard also left the game in that same inning after suffering a sprained left ankle on a collision at the plate with Pujols.
Corey Brock is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.