“Dang @calvinjohnsonjr, man, you had more years left …” Pittsburgh running back DeAngelo Williams tweeted following celebrated wide receiver Calvin Johnson’s NFL retirement announcement Tuesday.

Time was when we were shocked by those who left in the prime of their careers like Jim Brown and Barry Sanders.

But less and less with each passing season now.

Leaving with money on the table — $16 million in Johnson’s case — used to invoke remarks about a player’s sanity, but now it is increasingly viewed as a sign of acuity, if not a wish to preserve it.

In the wake of ever deeper, more disturbing revelations about what NFL players put their bodies and minds through, is it any wonder we see more and more calling it a career earlier?

We see them exiting sports’ biggest stage before being asked to and, in the case of the man known as “Megatron”, in spite of pleas to stay.

Johnson leaves the Detroit Lions after 83 touchdowns and at age 30 but recently we’ve seen several of his age — and younger — walk away from the game.

In just the last year linebacker Chris Borland exited at age 24, quarterback Jake Locker at 26. We wait to see if Anthony Davis (26) and Marshawn Lynch (29) will hold to their retirements.

Johnson didn’t say he was retiring for his health. But, then, he didn’t say much of anything in a true-to-his-nature brief statement confirming he had played, my last football game.”

His departure, however, comes amid a hard-to-ignore expanding list of former players found to have suffered from chronic traumatic encephalopathy (CTE) tied to repeated head blows.

Researchers from Boston University have published findings that 87 of 91 deceased NFL players studied suffered from CTE, including former New York Giants safety Tony Sash, who was 27.

Sash, who died of what was ruled an accidental overdose of pain medications, had suffered episodes of confusion, memory loss and erratic behavior. He was diagnosed with an advanced stage of CTE after his brain was donated posthumously.

After disclosures about Junior Seau and Tony Dorsett and the film, “Concussion” the topic has increasingly been tied to pro football. It was not a coincidence that the CTE Conference and second annual Neuro-Huddle hosted by the John A. Burns School of Medicine in conjunction with the Gary Galiher Foundation, was held the week of this year’s Pro Bowl.

For all the attention generated by the movie, keynote speaker Dr. Robert Stern of Boston University said concussions themselves, “are just the tip of the iceberg. That’s a big issue that people don’t typically get, that these long-term problems, like CTE, are not a consequence of concussions only. (They are) the result of repetitive hits that might be called sub-concussive, where there are no (immediate) symptoms associated.”

As part of his tweet to Johnson, @DeAngeloRB wrote, “… man the game will miss you but cornerbacks won’t lol goodluck in life.”

In the end, players are realizing that is what it is about, a better standard of post-football “life.”

Reach Ferd Lewis at flewis@staradvertiser. com or 529-4820.