Craig, 28, left the team's game against the Reds in the fourth inning after an awkward turn at first base while running out a grounder. Cincinnati first baseman Joey Votto dove for Craig's hit, but threw the ball over pitcher Bronson Arroyo's head. Craig rounded first, but twisted his foot in the process.
After the game, Craig was wearing a walking boot and underwent x-rays in the clubhouse, but tests did not give a conclusive diagnosis of the injury. The ailment is currently being classified as a left foot strain pending the results of his MRI.
Losing Craig for an extended time would be a blow to a Cardinals team that sits just one game behind the Pirates for first place in the NL Central. Craig leads the team with 97 RBI and has hit .315/.373/.457 with 13 home runs in 2013. He was named an All-Star for the first time earlier in the year.
Matt Adams replaced Craig at first base Wednesday.