Ramirez couldn't take the field in the bottom of the first inning of the series-opening defeat on Friday because of tightness in his right side.
Miguel Rojas, who replaced Ramirez on Friday night, will start in his place Saturday.
Ramirez was scheduled to undergo a MRI exam.
Ramirez said he felt discomfort when hitting in an indoor batting cage at
"It just tightened up on me," Ramirez said.