Detroit Lions receiver Calvin 'Megatron' Johnson retires from the NFL at age 30 - Los Angeles Times
Retired WR Calvin Johnson Explains Why Players Still Don't Self-Report Concussions - Steelers Depot
Calvin Johnson's retirement official
Detroit Lions Star Wide Receiver Calvin Johnson Unexpectedly Retires
Retirement? Calvin Johnson's decision may be more complicated than that
Calvin Johnson didn't like how the Lions treated him when he retired : r/nfl
Lions' Calvin Johnson makes 'difficult decision' to retire
Calvin Johnson claims Lions president immediately asked about bonus upon retirement - Pride Of Detroit
Calvin Johnson: I have played my last game of football - NBC Sports