Tight end Jeff Heuerman, the Broncos' third-round pick, suffered a torn anterior cruciate ligament in his left knee during the Saturday afternoon rookie camp practice in the Broncos' fieldhouse.
He is expected to miss the entire 2015 season.
Heuerman suffered the injury during the special-teams period of practice. He was running full speed down the middle of the field when he made a cut and his knee gave way.
A cart took Heuerman off the field, and a subsequent examination confirmed the worst fears of the rookie and the team.
"I feel terrible for Jeff and this is a very unfortunate situation," Head Coach Gary Kubiak said.