Carpenter is sidelined with a muscle strain behind his right shoulder and nerve irritation in his shoulder. He received an MRI on Friday as part of an attempt to establish exactly what is going on in Carpenter's throwing arm and how he can get back to full health.
"I'm still waiting to hear from doctors," general manager John Mozeliak said on Saturday. "We're waiting for a summary, a way to capture it."
The club expects to know something as early as Sunday.
Carpenter missed almost the first four months of the year as he recovered from Tommy John elbow ligament replacement surgery. He made three starts before going down with the shoulder strain, and the nerve issue was recently diagnosed.
Matthew Leach is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.