Ellsbury underwent an MRI that confirmed the initial diagnosis of a mild oblique strain and will be shut down for at least a week, Mark Feinsand of the NY Daily News reports. Both Ellsbury and manager Joe Girardi believed it was a minor issue and were hopeful that the 31-year-old could return to Grapefruit League action as soon as Friday, but after the MRI he'll stop baseball activity for the next seven days. His Opening Day status could potentially be in jeopardy if the timetable is extended any further, but for now he's on track to return toward the end of spring training.