On the same day that Evander Holyfield went broke, Floyd Mayweather, Jr. announced his retirement. He’ll be back. Sadly, maybe they both will.

I say this not based on any inside information. I say this based on 30 years spent around prize fighters. They all leave. They nearly all come back, as long as someone will have them.

One of the few exceptions was Marvelous Marvin Hagler, who left the sport and the country after not being awarded a victory over Sugar Ray Leonard on a night when he felt he deserved one. Hagler was, in many ways, the rare exception. He was truly his own man. Perhaps Mayweather will be too, but that’s not likely because at 31 he may be burned out with boxing but he is retiring, as he admitted himself when he made the announcement Friday night, “…knowing I still have my God-given abilities to succeed and future multi-million dollar paydays ahead, including one right around the corner. But there comes a time when money doesn’t matter. I just can’t do it anymore. I have found a peace with my decision that I have not felt in a long time.’’

How, you ask, can a young athlete at the very top of both his game and his sport just walk away like this with a potential $20 million or more on the table to fight again? For the long term he probably can’t but for the moment it seems likely that Mayweather left because, just as he said and just as his sad face and wet eyes have confirmed so many times in public, “…after many sleepless nights and intense soul-searching I realized I could no longer base my decision (to continue fighting) on anything but my own personal happiness, which I no longer could find.’’

Looking from the outside it may be difficult to fathom what Mayweather is talking about. He has fame, fortune (as he feels obsessed with telling everyone) and anything money can buy. What he doesn’t have, never had it seems, is peace of mind. To find that, he must flee his art, which is what prize fighting is to him.

For all his flamboyance and fame, for all his talent and style, Floyd Mayweather, Jr. has always seemed like a sad child in need of a hug. To be so clearly the best in the world at what you do and still be so obsessed with screaming, “Look at me! Look at me!’’ spoke loudly of a child long neglected by the people who should have known better. Frankly, if you had his family you’d feel the same way.

And now here he was, facing a three-ring circus the likes of which even the Mayweather clan had never seen before if he went through with a much-discussed Sept. 20 rematch with Oscar De La Hoya. Staring back at him from the opposite corner and from every HBO 24/7 Countdown show and lingering on the edge of every interview he would have to do would be the snarling, unforgiving face of his father, Floyd Sr., the man who had chosen to accept money to sell out his own son and train De La Hoya in the sly art of how to beat him up.

It seems unlikely that the younger Mayweather actually believes there are secrets about him only his father knows but who can say? Probably not even the son. That is not the point any way.

The point is what kind of father would agree to such a thing? The kind you walk away from, which is what the son just did.

Certainly De La Hoya believed the father had the key to beating his son somewhere in his twisted mind. It is why he turned away from Freddie Roach, the veteran trainer who prepared him so well for the first fight with Mayweather that he nearly won it and might have actually done so if he’d stuck with Roach’s plan. It is why he re-hired Mayweather’s father, feeling he knew weaknesses no one else would for he was the man who created what had become a fierce fistic machine.

Imagine the thought of it though. Think of the utter crassness of the idea that you would accept money to prepare another man to professionally assault your son. Think what that says about you but more than that think what it says to your son.

This decision was not an easy one for me to make as boxing is all I’ve done since I was a child,’’ Mayweather wrote in a prepared statement he sent out to the media. “However, these past few years have been extremely difficult for me to find the desire and joy to continue in the sport.

“I have said numerous times and after several fights over the past two years that I might not fight again. At the same time, I loved competing and winning and also wanted to continue my career for the fans, knowing they were there for me and enjoyed watching me fight.’’

Yet neither a brilliant career in full bloom, or an unbeaten record of 39-0 or his status as the universally recognized pound-for-pound best fighter on earth were enough to convince Floyd Mayweather, Jr. to put himself in what would surely have become a demeaning daily debate with a man he has been forced to accept is his biological father but a father by no other measuring stick.

The pain that must cause, the sadness that has forced him to endure, has sucked much of the joy out of boxing for a kid who once seemed to love the sport so. He probably still does love it deep down, which is why he will be back in a year or two or a month or two or maybe even a decade or two if he’s like George Foreman.

What is sure is one day Floyd Mayweather, Jr. will be back. What is sad is that he ever had to leave. And what is damn near criminal is what his father was willing to do for money.

Not even a boy tough enough to win world titles in five different weight classes could stomach the thought of that.