Calvin Johnson on a return to NFL: There's a lot of different things I can do, but football's not one of them - Pride Of Detroit
Calvin Johnson - Wikipedia
Calvin Johnson was a PFF all-timer before early retirement, PFF News & Analysis
Calvin Johnson says players could get painkillers like candy
Calvin Johnson Officially Retires From the NFL, News
After Calvin Johnson retirement, sources say Lions signing Marvin J.. - ABC7 Chicago
Calvin Johnson Reveals When He Decided to Retire from NFL, News, Scores, Highlights, Stats, and Rumors
Scott Linehan fondly remembers his time coaching Lions' Calvin Johnson
Calvin Johnson Is Retiring From the NFL
Detroit Lions receiver Calvin Johnson officially retires from NFL