While the rig crew was attempting to slip and cut the drilling line, the Assistant Driller stood on the flanges of the side of the drill line spool. He did this to use his weight to turn the spool too spool off drilling line for slipping drill line. Once the spool started turning he was not able to get away from the spool and the momentum of the drum kept it turning. The turning drum trapped his foot between the spool and the spool stand frame, pinning his right foot. X-ray revealed no broken bones.