The Chicago Bears signed defensive tackle Landon Cohen Friday and placed defensive tackle Henry Melton on injured reserve because of a knee injury.
Cohen played 27 games, including five starts, with the Detroit Lions (2008-09), Jacksonville Jaguars (2010), New England Patriots (2010-11) and Dallas Cowboys (2013), and has 32 tackles.
Melton has started 32 of 48 career games with the Bears. He has 71 tackles, 15.5 sacks, three forced fumbles, two fumble recoveries and nine tackles for losses.
Melton is out for the year with a torn ACL. He was injured against the Pittsburgh Steelers on Sunday night.
The 26-year-old was under a one-year contract at $8.45 million as the team's designated franchise player. Melton has been one of the best defense players for the Bears but he will enter free agency next year with some uncertainty.
Defensive tackle Stephen Paea may move over to the "three technique" that Melton played, while Nate Collins plays nose tackle. Undrafted rookie free agent Zach Minter is Melton's backup, but he has not been active so far this season.