Englewood, CO -- (Sports Network) - The Broncos on Tuesday placed linebacker Nick Greisen on injured reserve with a knee injury and signed linebacker Braxton Kelley.

Greisen played in 14 games -- one start -- for the Ravens last season, registering 11 tackles. He suffered the season-ending injury during the team's practice on Monday.

"(It is) unfortunate," Broncos head coach Josh McDaniels said of losing Greisen. "He is a great guy and a veteran player who understands what we are trying to do."

Kelley had been waived by the Broncos on June 11 and initially joined the club as an undrafted free agent on April 28. As a senior in 2008, Kelley was named the University of Kentucky's Most Outstanding Defensive Player after registering a team-best 98 tackles and four sacks in 13 games.