Although defensive end Israel Idonije just signed with the Detroit Lions a week ago, the team already knows him quite well. This is because he spent nine seasons in the NFC North with the Chicago Bears before coming to Detroit. He played against the Lions in one or two games in each of his nine seasons with Chicago, and he put up some pretty big numbers against his new team:
2012 (2 games): 6 tackles, 2.0 sacks, 1 forced fumble
2011 (2 games): 4 tackles, 1.0 sack
2010 (2 games): 8 tackles
2009 (1 game): 1 tackle, 1.0 sack, 1 forced fumble
2008 (2 games): 4 tackles, 2 passes defended
2007 (2 games): 1 tackle, 1 blocked kick
2006 (1 game): 0 tackles
2005 (1 game): 1 tackle
2004 (1 game): 2 tackles
Total (14 games): 27 tackles, 4 sacks, 2 forced fumbles, 2 passes defended, 1 blocked kick
Especially last year, Idonije did quite a bit of damage against the Lions, as he recorded a sack in each game against them. In the game at Ford Field, Idonije actually forced a fumble on his sack by stripping Matthew Stafford. Julius Peppers recovered the fumble, and the Bears took over at the Detroit 10-yard line as a result.
Given what the Lions' current regime has seen Idonije do against them since 2009, I guess it shouldn't have been a huge surprise that they decided to sign him. It's just surprising that they didn't add him earlier in the offseason. In any case, the Lions (and Stafford especially) have to be happy that Idonije is now on their team instead of a division rival.