Wallner was removed from Tuesday's game against the Marlins due to left oblique tightness, Do-Hyoung Park of MLB.com reports.
Wallner was grabbing at his left side after striking out during his pinch-hit appearance in the sixth inning. The Twins have now confirmed the issue to be in the 26-year-old's oblique, though the team will have to wait until Wednesday to determine the severity of his injury. If he needs to sit down for a game or two, Jose Miranda may be in line for more work as Minnesota's DH.