Reds beat reporter C. Trent Rosencrans tweeted the news Tuesday in the eighth inning of the game.
Rizzo has battled back pain before, including earlier this season when he left midway through an April game against Cincinnati.
The 25-year-old is hitting .278 this season with 29 home runs and 70 runs batted in. The Cubs beat the Reds Tuesday 3-0.
- Will Green