Calvin Johnson, a 2021 NFL Hall of Fame Inductee, gave his speech on Sunday in Canton, Ohio, last night where he talked about the reason he gave up football while still in his prime. Shockingly, after coming off a great final season, he retired after only 9 years, when he was 30 years old. He states that he gave up the sport because of a persistent injury that dated back to his very first season a professional.