McCullers (forearm) has been temporarily shut down from throwing, Chandler Rome of the Houston Chronicle reports.
Arm troubles limited McCullers to just eight starts last season, and while he doesn't seem to have a specific diagnosis beyond being "a little sore" at the moment, the fact that he's been shut down isn't encouraging. There's still plenty of time for this to turn out to be nothing more than a minor blip in McCullers' preparation for Opening Day, but he doesn't have the health track record to support a particularly optimistic outlook.