The move was announced as precautionary. Ramirez was replaced in left field by Bobby Kielty to start the bottom of the seventh. However, Red Sox manager Terry Francona indicated that he would not rush Ramirez back into the lineup on Wednesday night.
Kielty also left the game with back stiffness and was pinch-hit for by Eric Hinske in the eighth inning.
"He's been battling it since he hit the wall [on Aug. 19]," Francona said of Kielty. "When he went in there, it got real tight in a hurry. Rather than lose people for an extended period of time, we'll try to do the right thing."
The back issue has been ongoing for Ramirez for about the past week.
"His back spasmed up a little bit," said Francona. "After he took the one swing [for a single in the sixth], you could kind of see him moving around, and we all know he's been battling it for a little while. We'll see. I'm not a big fan of losing him for a couple of weeks, so we'll see how he shows up [Wednesday]. Again, we don't want to do something we're not supposed to do."
Ramirez was out of the lineup last Wednesday against the Rays and again on Sunday in Chicago.
Ramirez is hitting .292 with 20 homers and 86 RBIs.
Ian Browne is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.