Rizzo didn't participate in Tuesday's intrasquad game due to lower back tightness, Jordan Bastian of MLB.com reports.
The 30-year-old has battled intermittent back issues throughout his career, so it's not much of a surprise to see the Cubs being cautious early in summer camp. Still, it's a somewhat worrying development following the extended hiatus, especially with scheduled off days at a premium during the shortened 60-game season. Rizzo may lay low for a couple days but hopefully will make a relatively quick return to the field. Manager David Ross plans to bat his first baseman second in the order, with Kris Bryant batting leadoff.