EMPLOYEE SAYS HE WAS PICKING UP A 10"" BUFF BLOCK TO PALLETIZE AND FELT HIS BACK STRAIN. HE REPORTED TO HIS IMMEDIATE SUPERVISOR, AND THEN LATER REPORTED TO THE GENERAL MANAGER AS HE WAS LEAVING EARLY FOR THE DAY. HIS COMMENT THEN WAS THAT HE NEEDED TO GO HOME AND SEE IF HE COULD START FEELING BETTER.