"His shoulder bothers him, so we're just going to put [Jake] Fox over there at third base [Sunday]," manager Lou Piniella said after Saturday's 6-5 win. "We'll get him out of there tomorrow for sure, and we'll see how he is on Monday."
Ramirez spent nearly two months on the disabled list, May 9-July 6, with a dislocated left shoulder. He suffered the injury May 5 in Milwaukee after diving for a Ryan Braun ground ball in the third inning.
"It's been sore for a while," Ramirez said. "I was dealing with the pain. I was good enough to play, but today I couldn't."
Ramirez's only defensive action Saturday came on a grounder to third from Troy Tulowitzki in the fourth inning. Ramirez had trouble picking up the hard-hit grounder, but it was hit right to him and didn't appear to tax him in any way. He was charged for an error.
"Every time I swing the bat, I finish high with my left hand, so it's pretty sore every time I swing," Ramirez said, noting that there hasn't been any one event to aggravate the injury.
Having put Carlos Zambrano on the disabled list earlier Saturday, the Cubs are concerned about losing Ramirez. He is one of the hottest hitters on the club, posting a .317 average with nine home runs and 33 RBIs in his injury-shortened season.
"We've been through a lot this year, but we're still only a game out of first place," Ramirez said. "Hopefully it's just a one-day thing and I'll be back in there Monday."
Piniella marveled at the string of health issues that have hit the club this season, a litany that was softened with Saturday's victory.
"This has been a season for all seasons with the adversities we've had," Piniella said. "What are you going to do? You just got to keep playing and tough it out. And that's what these guys are doing, believe me."
Owen Perkins is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.