On 8/7/14 while moving a hyd. pump, the pump slipped out of ee's hands. The other 2 ee continued to load the pump. At the time the affected ee felt no discomfort and did not report anything to supervision. On Sat 8/16/14 the affected employee went to Urgent Care complaining of back pain related to this incident. EE was placed on restricted duty by Mosaic Co PA on 8/18/2014.