I used to think professional sports were about sports.

Silly me.

Sports are really not about sports anymore.

They are about entertainment.

And about celebrity in a celebrity-crazed culture.

And the past month or so we’ve had several examples, certainly, the most notable being A-Rod, Manny and Brett Favre, three men who long ago transcended sports. In fact, if you see them as celebrities first, and athletes second, so much of what’s taken place in the last six weeks or so starts to make more sense.

Consider A-Rod, who long ago stopped being merely a baseball player, courtesy of his huge contract, playing in the media fishbowl that’s New York.

Or you don’t live on the front page of the New York tabloids by being merely a baseball player.

But that’s been much of his address much of the summer, as his alleged relationship with Madonna, his failed marriage with a wife now commonly referred to as C-Rod, and his alleged past extramarital affairs have made his life seem like a specimen under some laboratory microscope. All splashed across the front pages of the New York tabloids.

This is sports?

Not really.

This is celebrity.

And it makes no difference what his batting average is, or how he hits in the clutch, how the Yankees do, or even who he really is. If that’s even possible to know anymore. Alex Rogriguez lives inside the birdcage that’s become celebrity in America.

Consider Manny, whose appeal to so many Sox fans had more to do than just his ability to hit a baseball.

In a sense, he was the barometer about how things have changed. For all the baseball purists who appreciated his talent, there were those who liked him simply because he was quirky and different, Manny being Manny. For all the baseball purists who came to tire of his disrespect of the game, there were still legions of fans who believed Manny could do no wrong.

Celebrity makes you bulletproof. It’s why bad girls Britney Spears and Lindsay Lohan are still superstars regardless of their past transgressions. It’s why rock stars get a free pass. It’s why actors and entertainers can go to rehab like other people go to a spa, and it does nothing to hurt them at the box office. It’s why Paris Hilton is always in the news, even if her personal life is a train wreck and she has no discernible talent, as if celebrity is a thing in itself.

If Hollywood always has understood this, it’s hard to pinpoint when it also became part of professional sports.

The phenomena of Joe Namath in the late ’60s certainly was one of the first precursors, with his “Broadway Joe” nickname, and the endless stories about his lavish penthouse and his starlets. Football player as rock star.

But it was George Steinbrenner who was one of the first of the contemporary owners who understood that professional sports was show business, no different than the new Broadway play.

Part of it was ego, certainly. Steinbrenner loved seeing his name splashed across the back pages of the New York tabloids. But when he bought the Yankees, in 1973, he had already invested in some Broadway shows, and he knew that it was all about star power, all about selling tickets.

That’s one of the reasons why he wooed Reggie Jackson in the fall of 1976, why he took him to lunch at a fashionable spot and then walked with him down Fifth Avenue, why Jackson later said that Steinbrenner courted him as though he were a woman. It’s one of the reasons why the Yankees under Steinbrenner became all about stars, for he knew that America loved stars, that people all but genuflected in front of them.

Isn’t that what we’re seeing now with the Jets and Favre?

There’s no way that a 39-year-old quarterback in the twilight of his career, a man who is obviously conflicted as to whether he even wants to play anymore, is the right move for a franchise. In the best of worlds, it’s a quick fix for a team in the NFL netherworld. In the worst of worlds, it’s football fool’s gold, and it hurts the development of the team.

But for entertainment value?

It’s already paying off.

From the 10,000 people that watched a Jets’ practice, to the Favre shirts that are running a fly pattern out of New York stores, to Favre posing for pictures with Mayor Michael Bloomberg, the Jets are back on the radar screen again.

For Favre no longer is just a quarterback, great as he was. He is a celebrity, someone whose name long ago jumped off the sports page. Star power.

That’s what we’ve been seeing this summer, A-Rod, Manny, Favre.

More examples that this is all about entertainment, even if we used to think it was about sports.

breynold@projo.com