Sale (ribs) was scheduled to undergo a pre-planned MRI on Thursday, Ian Browne of MLB.com reports.
The MRI isn't the result of any setback in his recovery from a stress fracture on the right side of his rib cage; instead, Sale is being sent in for imaging so he and the Red Sox can assess how much his ribs have healed since he was shut down in mid-March. If the imaging shows the desired improvement, Sale could resume throwing before the end of camp, though he'll stick around at extended spring training in any case while he opens the season on the injured list.