EE WAS ON DREDGE MOVING CABLE, ANOTHER EE WAS ON BANK ON TRACTOR. CABLE BECAME TANGLED ON DREDGE & WHILE INJURED EE WAS WORKING TO UNTANGLE CABLE, EE ON TRACTOR MOVED SLOWLY AHEAD & PULLED INJ URED EE'S ARM, INJURING HIS SHOULDER. INJURED EE DIDN'T REPORT PROBLEM UNTIL 2/23/00 & WENT TO DR ON 2/24/00. EXTENT OF INJURY NOT KNOWN AT THIS TIME. EE SCHEDULED FOR MRI ON 3/1/2000.