The Chicago Tribune and the Chicago Sun-Times report the netting would go up as a precaution after engineers finish an inspection of the stadium's upper deck.
Cubs vice president Mike Lufrano declined to discuss the workers' findings or whether the inspection will be finished by the team's next home game on Friday. The inspection began last Friday.
On Wednesday, a Cubs employee found a palm-sized piece of concrete that apparently fell from the stadium's upper deck. It was the third such incident at the 90-year-old stadium in less than two months, but no one has been hurt.