The Rockies announced Monday that Petit has been diagnosed with a UCL sprain in his right elbow, Thomas Harding of MLB.com reports.
The diagnosis is often a precursor to UCL surgery, but Petit will consult with doctors before making a decision. A Rule 5 pick, Petit could be stashed on the 60-day injured list while he recovers, though the Rockies would still have to follow regular Rule 5 roster guidelines once Petit is off the 60-day IL.