The Steelers placed Lee on injured reserve Saturday due to a calf injury, Brian Batko of the Pittsburgh Post-Gazette reports.
Lee was already ruled out for Sunday's regular-season opener against the Falcons after logging DNPs for all three practices. His calf injury is severe enough for him to go on IR, and the rookie sixth-round pick will have to sit for at least four games. The earliest Lee can return is Week 5 against the Cowboys on Oct. 6.