Following Some Heavy Lifting A Month Ago, With No Abrupt

Following some heavy lifting a month ago, with no abrupt pain noted, I noted the next day I was unable to abduct my arm more than about 20 degrees. By MRI I have a "2/3" tear of the supraspinatus tendon, on that shoulder where the same tendon was surgically repaired 2 years ago. Trying to abduct the arm doesn't hurt, it just doesn't raise up. My orthopaedist thinks another rotator cuff repair is in order; I'm concerned it may not be effective if the axillary nerve is actually damaged. Should I insist on getting an MRI directed at the Axillary nerve?