Giolito (hamstring) is scheduled to undergo an MRI on Wednesday, Ian Browne of MLB.com reports.
The 30-year-old said after departing Tuesday's spring game that he believed the hamstring tightness to be a "very minor" injury, but he's still headed for medical imaging. Giolito may not miss much time if the MRI comes back clean. If the MRI reveals anything concerning, Giolito would likely begin the season on the injured list.