Prosinski finished third on the club in special teams tackles last year, and started one game at safety. The veteran is viewed as an important reserve, who joined Chicago in 2015 following stops in Philadelphia and Jacksonville.
Prosinski appeared in all 16 games last year. He made five starts in 2015, recording nine tackles in Chicago's upset victory at Lambeau Field on Thanksgiving night.
The Bears are in the process of overhauling their secondary. Chicago signed cornerbacks Prince Amukamara ($7 million) and Marcus Cooper ($6 million) and safety Quintin Demps ($4.5 million) to sizeable guarantees for the upcoming season. The Bears could also target a safety with the third overall pick in next month's draft. LSU's Jamal Adams and Ohio State's Malik Hooker are the top rated safeties in the class. Both might appeal to the Bears, who are also known to think highly of Stanford defensive end Solomon Thomas. The best scenario for Chicago is to move out of the third slot and stockpile extra picks, but finding a trade partner may be difficult given the underwhelming 2017 quarterback class.
In other news, the Bears agreed to terms with defensive lineman CJ Wilson, according to Wilson's agents.
A seven-year NFL veteran, Wilson previously played for New Orleans, Detroit, Oakland and Green Bay.