Mon 6/17/13 5:24 PM

Cardinals manager Mike Matheny said that Chris Carpenter felt some back stiffness during a long bullpen session Sunday. It's not clear if Carpenter will have to scale back his throwing program, but he'll likely need a few more bullpen sessions before the Cardinals think about the possibility of a rehab assignment. While it once looked like the veteran right-hander could return in late June, sometime during the second half appears more realistic at this point.