Sandoval sat out Wednesday's series finale against the San Diego Padres. With an off day Thursday, Giants manager Bruce Bochy said the team will wait until Friday to decide whether Sandoval needs to be put on the disabled list.
Sandoval shifted to first base in Tuesday night's 3-2 victory against the Padres. He left the game after three innings when he strained his hamstring stretching for a catch to finish a double play.
Sandoval is batting .299 with eight home runs and 33 RBIs this season. He missed more than a month already this year after surgery to remove a broken hamate bone in his left hand.