Callahan is the second unrestricted free agent defensive back Denver has signed in free agency, joining former Houston Texans hard-hitter Kareem Jackson in the “No Fly Zone” Version 2.0.
Callahan joined the Bears as a college free agent out of Rice University in 2015 and has 122 tackles, four sacks, four interceptions, 20 pass breakups and a forced fumble in four NFL seasons.
He started 10 games and appeared in three more with the Bears last season when he posted a career-best 45 tackles to go with two sacks, two interceptions and six pass breakups. He allowed just one touchdown.
The Broncos also re-signed tight end Jeff Heuerman, one of their own unrestricted free agents, to a two-year, $9 million contract Friday.