Cardinals first baseman Albert Pujols was hurt on a play at first base in the sixth inning and left Sunday's game against the Royals.
A Cardinals spokesman said a preliminary evaluation revealed Pujols sustained a sprain to his left wrist, but tests are pending.
He will receive further evaluation Monday, an off day for the Cardinals.
"To be honest, I can't give you guys too much until the X-rays and an MRI tomorrow," Pujols said. "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."
Pujols Sprains Wrist, Tests Pending