Boomer Esiason
Esiason remains a Cincinnati legend and was undoubtedly good during his time with the franchise. The quarterback starred for the team for nine seasons before he returned in the twilight of his NFL career. They traded him to the Jets during a typically turbulent period for Gang Green (via Cincinnati.com).
He received a brutal hit that resulted in a massive concussion in 1995. This put him out of the game and many people thought that he would quit after this. Arguably, he held on for too long because he went to Arizona before his return to Cincinnati and risked his health.