The Bears have yet to officially announce the signing. A corresponding move will be required to add the 27-year-old Urban to the active roster.
A six-year NFL veteran, Urban was recently released by the Titans. He played his first five seasons with the Ravens organization. He has 3.5 sacks over 45 regular-season games in his career.
The Bears placed Pro Bowl defensive lineman Akiem Hicks on injured reserve last week due to an elbow injury. The team is hopeful Hicks can return to game action later this season, but the earliest that could be is against the Packers on Dec. 15.
The Bears (3-3) host the Chargers (2-5) at Soldier Field this Sunday.