Rizzo has not played since his back tightened during a rain delay in the Aug. 26 game in Cincinnati. The Cubs had hoped the first baseman would return Monday against the Reds.
"That one I will reserve for [Monday]," Cubs manager Rick Renteria said. "We're trying to get him out there running. I'd still look more ahead, and take anything sooner as a plus."
The Cubs are taking a conservative approach with Rizzo, who is batting .278 and hit his 30th home run in his last game.
"I don't want to put a date on [his return]," Renteria said. "Let's hope that sometime in the coming week we'll see something and go from there. If it happens to be much sooner than later, good for us."
Carrie Muskat is a reporter for MLB.com. She writes a blog, Muskat Ramblings, and you can follow her on Twitter @CarrieMuskat. This story was not subject to the approval of Major League Baseball or its clubs.