Idonije played for the Detroit Lions last season with 11 tackles and a half-sack.
When he played for the Bears from 2010 and 2012, Indonije had 149 tackles, 20 1/2 sacks and five forced fumbles.
Indonije, 33, is regarded highly for his savvy and ability to line up at both defensive end and defensive tackle.
The 6-foot-6, 275-pounder has 289 career tackles, 29 sacks and six forced fumbles.
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Aaron Wilson covers the Ravens for The Baltimore Sun