The 24-year-old Walker played the last two seasons with the New Orleans Saints. He made one start in 2014, finishing the season with 2 1/2 sacks.
The Lions lost star defensive tackle Ndamukong Suh to free agency, but they've already added a couple defensive players in the last few days. Detroit acquired defensive lineman Haloti Ngata in a trade with Baltimore, and now the Lions have reached a deal with Walker.
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