Lee, who spent his entire 11-year NFL career with Dallas, told ESPN's Todd Archer of his plan to walk away. The Penn State product's career was marked by injuries, which limited him to 118 games played.
Lee told Archer:
"It's been a complete honor. I've been blessed to play for the incredible Jones family, with such great coaches and teammates that I love like brothers. I loved every minute playing and tried to pour my heart and soul into winning and helping my teammates at all costs.
"To say the injuries were frustrating would be an understatement, but the support I received through them all was humbling and the lessons I learned battling adversity will last a lifetime. There are always regrets, but I'm proud of what I was able to accomplish and I leave this game grateful."
When Lee was on the field, he racked up tackles better than nearly any linebacker in the game. He set a Cowboys record with 22 tackles against the New York Giants in 2016 and posted four 100-tackle seasons. The 2016 campaign was his finest as he set a career high with 145 tackles and earned first-team All-Pro honors.
Unfortunately, Lee couldn't avoid the injury list. He played 16 games in a season only once as a litany of ailments—including a toe injury in 2012 and a torn ACL in 2014—cost him playing time and, eventually, his effectiveness. After a core muscle injury held him out of the first seven games of the 2020 season, he returned to the Cowboys but ranked as one of the NFL's worst linebackers in Pro Football Focus grading.
While no one would question Lee's locker-room impact—teammates glowed about his leadership ability—his injuries derailed a potential Hall of Fame career.