ON MONDAY 4/30 IT WAS DETERMINED THIS INJURY WOULD BECOME A DEG.3. AFTER REVIEWING MEDICAL REPORTS, EE WAS INJURED 3/6 DOUBLING FROM GRAVES TO DAYS TO WORK ON MII OUTAGE. WHILE PULLING A NEW SCREW SECTION INTO POSITION IN SCREW HOUSING, OFCS-3606 EE FELT A POP IN HIS RT ARM. DIAGNOSIS WAS A BRACHIORADIALIS MUSCLE STRAINE