The Chiefs placed Bell (hip) on injured reserve Monday, Aaron Wilson of ProFootballNetwork.com reports.
Bell underwent surgery to address a hip flexor injury in late August and doesn't yet have a timetable for return, but he'll be forced to miss at least the first four weeks of the regular season. Once the 2015 fourth-rounder is back to full health, he's expected to serve as depth at tight end behind Travis Kelce.