An examination of Walker's forearm Tuesday revealed that he's dealing with a UCL injury, Steve Gilbert of MLB.com reports.
While it's known that Walker suffered a UCL injury, manager Torey Lovullo was unsure if it's a tear. Per Gilbert, Walker is scheduled to receive a second opinion on the injury in New York in the coming days, after which it should be revealed how the righty will proceed and whether or not he'll require surgery.