Here is a statement released by Bears GM Ryan Poel following the news:
Mastrantonio is an NFL Certified Contract Advisor working with Shark Sports Management which is a full-service sports agency.
The 30-year-old Naperville, Illinois native played his college football at Illinois State and was a 2015 fifth-round draft pick of the Kansas City Chiefs. He played two full seasons in Kansas City before being traded to the New England Patriots.
He did not play a lot in New England and he then was signed by the Jacksonville Jaguars where he played the past 5 seasons.
He was actually on pace to have by far his best season last year. Through 6 starts, he caught 24 passes for a total of 244 yards. If you average that to 17 games, this becomes 691 yards. 40 yards per game for a tight end is really solid.
Here are a few of his highlights: