Speaking at his football camp in Michigan on Saturday, per Michael Rothstein of ESPN.com, the three-time All-Pro wide receiver said he thought about hanging up his cleats when the Detroit Lions lost that controversial playoff game against the Dallas Cowboys in January 2015.
Johnson, however, decided against that because, he said, he "felt like [he] could do it again." He knew going into the 2015 season, though, that it would be his last and told family members and some teammates.
He did not say why he decided to walk away at the age of 30, per Rothstein:
I know everybody wants to know why I retired, but it's more so I put a lot into the game and it's taken a lot out of me and that's where I'm at right now. I'm not getting into the specifics of the things that it has taken away, but it definitely feels good, I guess I could say for myself, to spend more time around my family, my son, just got married.
Johnson said that at "some point, if you got any bit of intelligence about yourself, you gotta think about what's going to happen" after football. He'd like to finish his degree at Georgia Tech, host more camps and dive into his Calvin Johnson Jr. Foundation, per Rothstein.
Johnson also said his decision was not related to the Lions' struggles on the field: "I wouldn't just quit because we were losing. Just [my] body, man, I was tired of it. I was fed up. Had enough."
Former offensive lineman Rob Sims, who played with Johnson in Detroit from 2010 to 2014, told Rothstein that Johnson "really played through some stuff that a guy of his caliber doesn't usually do." Sims recalled "picking [Johnson] up a couple times and being like, 'God, man, you should not be in this game right now.' But we needed him."
Johnson was clear that he will not waffle: "I'm not coming back. You ain't gotta worry about that.
"It's my decision. I made my own decision. I'm good with it."
It would be hard for a player to give more of himself to a team than Johnson did to the Lions over nine seasons. He missed just nine games in his career and helped lead the franchise to two playoff appearances.
Even though things ended sooner than Detroit fans would have preferred, Johnson lived up to his potential—and then some—as the No. 2 pick in the 2007 draft.