The Broncos' search for veteran depth continued Monday when they signed 36-year-old linebacker Keith Brooking to a one-year contract.

Brooking's arrival comes two days after the Broncos signed ex-Jets/Ravens/Bills safety Jim Leonhard. Denver placed Leonhard on the active/PUP list while he gets his troublesome knee into playing shape.

The addition of Brooking appears to be an indictment on the Broncos' depth at linebacker.  With D.J. Williams facing a six-game suspension to start the season, the Broncos' projected second team consists of Danny Trevathan, Mike Mohamed and Nate Irving -- none of whom has started in the NFL. Irving played all 16 games last year but did so almost exclusively on special teams and only logged one defensive tackle.

The Broncos wouldn't have to cut anyone to sign Brooking; they placed running back Mario Fannin on injured reserve with a torn Achilles tendon Monday morning, freeing up a spot.

Brooking turns 37 on Oct. 30 and would become the oldest player on the Broncos' roster. In spite of his age, he has been remarkably durable; he has an active streak of 176 consecutive games played dating back to 2001.

Brooking had been with the Dallas Cowboys the last three seasons after spending 11 years with the Atlanta Falcons. Broncos coach John Fox knows Brooking well from his days with the Carolina Panthers; they've squared off 15 times, including once during a Cowboys-Panthers game in 2009.

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