Darlington: In the saddle again
Koppen, who turns 33 on Wednesday, adds experience and depth to the interior line and might push starting center J.D. Walton for playing time.
Manning was sacked twice in his Denver debut, once when it appeared the wrong line call shifted everyone to the right and led to left tackle Ryan Clady having no one to block. Running back Knowshon Moreno was left to block two men, and Pittsburgh linebacker Jason Worilds dropped Manning for an 8-yard loss.
The offensive linemen weren't in the locker room during the media access period Tuesday.
As expected, the Broncos also placed defensive tackle Ty Warren on injured reserve after he re-tore his right triceps in the opener, his first game since 2009.
"It affects us a lot, actually," said second-year defensive tackle Mitch Unrein, who played a career-high 40 snaps after Warren got hurt. "He's a great leader. but as Coach (John) Fox always says, next guy up, so that kind of opens the door for guys like me."
The Associated Press contributed to this report.