On the day after Calvin Johnson, among the greatest players in Georgia Tech annals and until recently the NFL’s best receiver, retired at 30, Taz Anderson was in Piedmont Hospital, recovering from hip-replacement surgery. Anderson was a Tech co-captain under Bobby Dodd and played seven years in the NFL, the final two with the expansion Falcons. This week’s surgery was his 43rd. Thirty of those he considers the cost of a football career.

Asked about Johnson’s retirement, Anderson said: “It’s the smartest thing you can do.” He’s 77, and even a stint in the pre-merger NFL — when the game was slower and players didn’t train year-round — literally scarred him for life. He takes inventory of surgeries: “Let’s go from the ground up: An ankle; both knees done several times; both hips; five (on the) back; both elbows.”

With every year, we learn more about the lasting damage the game inflicts. For those who've already been damaged, such findings come as cold comfort. Peyton Manning retired this week at 39, having needed three rounds of neck surgery to fashion the second act of his career. Last year he told SI.com he had no feeling in his fingertips and mightn't ever again.

Joe Montana told USA Today last month he can't run and will need a knee replaced. He has had elbow surgery and three installments of neck fusion. He has nerve damage to an eye. His hands hurt so badly the pain wakes him in the middle of the night.

These are NFL poster boys, Montana and Manning and Megatron. These are guys who made millions and were the best in their business. But they’re human, and the human body can and does break.

“I’m going to guess that Calvin has an injury he knows is not good,” said Anderson, an Atlanta entrepreneur and one of Tech’s biggest boosters. (FYI, Johnson has had knee and ankle injuries.) “I had to have a knee done when I quit. I knew exactly what was going to happen.”

Then: “There’s the current injury and then the long-term injury. When you retire, you’re probably going to have an operation on something that’s been bothering you — ankle or knee. Later on, it’s hips or shoulders. You’re not going to get out of there without something needing to be fixed.”

The New York Times recently profiled Willie Wood, whose interception return was a highlight of the first Super Bowl. He's 79. He resides in an assisted-living facility in Washington, D.C. He doesn't recall the interception. He doesn't recall the Super Bowl. He doesn't recall his 1989 induction into the Pro Football Hall of Fame.

“Great player,” said Anderson, the former tight end, of Wood, the Green Bay safety. “He hit me from behind one time. I ran a down-and-out. He came up and hit me on the left side of my head. That’s the last I remember about the play. I do remember everybody in the stadium laughing at me when I tried to get up and was wobbly.”

We wouldn’t laugh today. (Or else shame on us.) We’ve heard too much about concussions and their aggregate effect. We know that chronic traumatic encephalopathy has been found in dozens of former players — or, more precisely, in their bodies. CTE can be discovered only post-mortem.

The NFL Players Association gave its members passes to see the movie “Concussion.” Anderson attended a screening. The film was sobering. It was also no surprise to anyone there.

Said Anderson: “It’s the same action on every play. You stop and start, and your head does the same thing. The skull is a rigid container. It absorbs an impact on every play. … Run your car into a tree at high speed, and you’re going to get something (bad) out of it.”

At some point, a player has to ask if it's worth it. More guys are deciding it isn't. Jerod Mayo, a former All-Pro linebacker who ended the past three seasons on injured reserve, announced his retirement from the Patriots last month at 29. Patrick Willis retired from the 49ers last year at 30 after a toe injury. His teammate Chris Borland retired after his rookie season because of concerns over head trauma.

Dr. Allan Levey is the chairman of Emory’s neurology department. He has done what he calls “informational sessions” with several ex-players — he recalls one “hobbling up, almost in tears” to say thanks — and has seen lingering physical injury become something worse. “The compounding of all the medical conditions related to the neurological can lead to emotional and cognitive problems,” Levey said. “Families dissolve around them. It’s incredibly sad.”

Soon, it will be difficult to pretend that the NFL isn’t just a blood sport — like boxing, like mixed martial arts. As much as the league can try to make conditions safer for players, it can never make them safe. These are big and fast men running into one another, an experience Anderson likens to “having a load of cement dropped on you.”

Playing pro football seems glamorous until you actually do. Then you know better.