Retired Calvin Johnson told ESPN E:60 that he took painkillers "every day" during his playing career.
Calvin Johnson said he knew 2015 would be his last year in the NFL before the season began.
Matthew Stafford said he thinks Calvin Johnson is retired for good.
Lions WR Calvin Johnson announced his retirement from the NFL after nine seasons.
The Detroit Free Press reports the Lions "hope to know" Calvin Johnson's 2016 status in the next 24 hours.
Yahoo's Charles Robinson reports Calvin Johnson "has no money concerns" and isn't attempting to lure a raise out of the Lions with his retirement plans.
The Detroit Free Press' Dave Birkett tweeted Sunday his "final prediction" on Calvin Johnson is that Johnson retires.
Lions president Ron Wood said Calvin Johnson has yet to decide if he will retire.
Golden Tate said Calvin Johnson's "body just isn't holding up."
Lions president Rod Wood is hoping to introduce Calvin Johnson to GM Bob Quinn sometime next week.
ESPN's Adam Schefter reports the Lions informed coaching candidates during their 2014 search of "concerns doctors had for [Calvin] Johnson's longevity and the condition of his ankles."
NFL.com's Ian Rapoport reports the Lions' "goal" is to retain Calvin Johnson with a Larry Fitzgerald-esque extension.
NFL.com's Ian Rapoport reports Calvin Johnson has already called Lions ownership to "thank them for everything."
According to ESPN's Adam Schefter, Calvin Johnson told Lions coach Jim Caldwell that he plans to retire.