Gary M. Pomerantz is the author of THEIR LIFE'S WORK: The Brotherhood of the 1970s Pittsburgh Steelers, Then and Now (Simon & Schuster). He agreed to a guest submission to BTSC about the Steelers' decision to retire Joe Greene's number. This column originally ran July, 2014

When I heard the other day that the Steelers had retired Mean Joe Greene's jersey No. 75, I thought, "Well, of course!"

Greene was not only the greatest Steeler in history, but the most transformative. He was the foundational piece of the 70's empire.

Ernie Holmes once grumbled that he was underappreciated, underpaid and every bit as talented at defensive tackle as Greene. Remembering that moment years later, the Steeler scout Bill Nunn would roll his eyes, and say, "Joe Greene made a whole lot of people think they were better than they were."

Surely Greene had the finest nickname in football history. (A possible runner-up - the Eagles' Chuck Bednarik, aka Concrete Charlie.) Greene was not the biggest, strongest or fastest among the members of the Steel Curtain front four during the 1970s. But he had a compensatory quality, a state of mind. He played with rage.

What he did on the field alone merits retiring his jersey. And what he did as the Steelers' de facto team leader from 1969 through 1981 merits close examination by those who study the qualities of dynamic leadership.

Greene led through the force of his personality. He kept the 70's Steelers in line.

Late in the 1975 season Greene confronted Steeler quarterback Joe Gilliam about his drug use. Gilliam told him to mind his own business at which point Greene, looming over him, grabbed Gilliam by the scruff of his collar, and said, "This isn't just you. It's the team."

At another moment, defensive coach George Perles counted only 10 of his Steeler defenders on the field. He spotted Holmes standing next to him on the sideline.

"What the hell are you doing here?" Perles asked.

"Joe threw me out of the game," Holmes answered, referring to Greene.

"What do you mean?" Perles said.

"I wasn't playing the defense," Holmes said, "and Joe said if I wouldn't do it, to get the hell out."

Perles: "Get the hell back in there!"

Holmes: "Naw, I'm not going back. Not until Joe tells me it's okay."

Now a 67-year-old grandfather, Greene still keeps his emotions close to the surface, except now the emotions are softer, more reflective. While interviewing him for my book, Their Life's Work, I asked him about the death of Dwight White, his great friend and fellow defensive lineman. Greene recalled receiving Franco Harris's phone call from a Pittsburgh hospital, saying, "He didn't make it." As he told this story, Greene inhabited that moment again, and his eyes filled with tears. He would eulogize White, Holmes and, more recently, L.C. Greenwood, and now is the only surviving member of the original Steel Curtain front four.

Steeler scout Bill Nunn would roll his eyes, and say, "Joe Greene made a whole lot of people think they were better than they were."

At another moment, in his living room in Dallas, we watched a DvD of the Steelers' Super Bowl IX victory over Minnesota. As the Steelers took charge of that game, Greene, sitting on his couch, began to chant, "Here we go Steelers, here we go!" He was joyful, young again.

It is appropriate that Greene's jersey should be retired. It's only the second time it has happened in franchise history. Ernie Stautner's jersey was the first, retired 50 years ago.

In the years ahead the Steelers should also retire the jerseys of the eight other Hall of Famers from the ‘70s empire - Lambert, Ham, Harris, Bradshaw, Blount, Swann, Stallworth and Webster.

It's possible that one day the Steelers will run out of double-digit jersey numbers. If so, we should celebrate that. I look forward to seeing Steeler players in the year 2034 wearing jersey Nos. 216 and 864.

Thanks to free agency, the salary cap and the laws of probability, we'll never see another team like the ‘70s Steelers.

And now we know that we'll never see another No. 75 again, either.