Rizzo's back became an issue on Tuesday when he couldn't get loose after a 50-minute rain delay in Cincinnati. He came out of that game as a precaution.
Rizzo has yet to be in the lineup since top prospect Jorge Soler was promoted from Triple-A Iowa.
"We all want to see [Rizzo] in that lineup," Cubs general manager Jed Hoyer said. "It'll be fun to see that lineup card. I don't have a prognosis [on Rizzo's status], just that he's day to day in the true sense of the word."
On Thursday, Rizzo said there wasn't one thing that aggravated his back, and called the problem "frustrating."
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.