Getty Denver Broncos head coach Sean Payton walks on the sideline before a game against the New Orleans Saints. The Denver Broncos are in the market for an upgrade at tight end, and one of the greatest in NFL history – former New England Patriots and Tampa Bay Buccaneers star Rob Gronkowski – may be eyeing a comeback. Gronkowski also has ties to the Broncos. Moreover, Gronkowski is said to have strong positive opinions on Broncos quarterback Bo Nix . “League sources have told me that Rob