EE STATED THAT HE WAS WALKING ALONG THE SIDE OF THE SECTION POWER CENTER WHEN HE STEPPED ON SOMETHING IN THE WALKWAY (DID NOT KNOW WHAT HE STEPPED ON.) HE STATED THAT AT THE END OF HIS SHIFT H E WAS EXPERIENCING SOME STIFFNESS TO HIS RIGHT KNEE. EE ALSO STATED THAT HE HAS HAD PROBLEMS WITH HIS RIGHT KNEE IN THE PAST. INCIDENT BEING REPORTED AS INJURY PENDING ADD'L MEDICAL INFO (MRI