Kim was scratched from his scheduled outing Saturday against the Marlins with a tight back, Zachary Silver of MLB.com reports.
The Cardinals aren't particularly worried about any long-term issues with Kim, but the setback may throw off his preseason preparation to the point that he's not quite ready to go by Opening Day. It doesn't appear as though he'd have to miss more than a turn or two in the rotation to start the year, but the Cardinals may now have two temporary spots opened up, as Miles Mikolas (shoulder) is expected to open the year on the injured list.