Manager Torey Lovullo said Wednesday that Burnes (elbow) has been shut down from throwing after suffering a teres major strain, Bob Nightengale of USA Today reports.
Burnes has been throwing to live hitters over the past couple of weeks while working his way back from a Tommy John procedure he underwent last June, and he reportedly felt something in his side/shoulder during his last session. The team is hopeful that the 31-year-old righty will still be able to return sometime in September, though a more precise timeline will likely take shape once he's cleared to restart his throwing program.