"It appears to be a bruise," manager Jim Leyland said, "but those can get pretty sore and they can linger a while. You don't know for sure. I don't have much else for you."
Ramon Santiago started in Infante's place Thursday.
The Tigers haven't given an indication that a stint on the disabled list is a consideration, but the schedule could work to their advantage if they chose to make the move. Since the four-day All-Star break would count among the 15 days, Infante could miss two weeks while missing far fewer games.
Jason Beck is a reporter for MLB.com. Read Beck's Blog and follow him on Twitter @beckjason. This story was not subject to the approval of Major League Baseball or its clubs.