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The eight-year veteran last played for the Seattle Seahawks, who signed him to a two-year deal in 2009. He played 27 games for the Seahawks, totaling 92 tackles, one sack and one fumble recovery. His main strength was in run defense, but was hobbled by ankle injuries in 2010 and the Seahawks did not re-sign him after the season. He has been out of the league since then.
Details of the contract are not known at this time, but it may not be for much, and it's unlikely that Carolina would commit to him as a starter when he turns 33 in June and hasn't played in two years. This move seems like a classic training camp flyer to see if a longtime veteran has anything left in the tank.