FORT WORTH, Texas — Seek Julio Franco, the man who would play baseball forever, and you discover more about a game’s magnetic hold than you would ever suspect.

That Franco, at 55, would uproot himself from the comforts a 23-season major league career can provide just to take a few more cuts against pitchers less than half his age is a wonder.

That he would believe himself still capable of putting good wood on real big league pitching if the opportunity arose is amusing. “Why not? If you throw it in my zone, I’ll hit it,” Franco said. “That’s my confidence. It’s only inside the individual that matters. The only thing that matters to me is inside my head when it comes to playing.”

That Franco thought he could almost literally roll off his couch back home in the Dominican Republic and pop up a couple of thousand miles away and play like it was 1990 was, as it turned out, a little overconfident. After playing for six consecutive days with the independent minor league team in Fort Worth, the Cats, his troublesome right knee began screaming at him last week. He planned to limp back to his island home, where he would weigh the option of surgery.

It looks, alas, as if he can be of no service to the Atlanta Braves’ struggling offense.

With the Braves, where Franco spent five of his last seven major league years as a first baseman and pinch hitter — with a little piece of the seventh season thrown in at the end — he became quite popular among those who wanted to ignore their birth dates. He was the guy to point to in order to defend the indefensible position that you really could be every bit as good as you used to be.

Before Franco was done, he became the oldest major league player to hit a home run, a pinch-hit home run, a grand slam. He was 49 when he got the last of his major league hits, in his final Braves at-bat, Sept. 17, 2007, off Lee Gardner of the Marlins. Right to the end, Franco preached the irrelevance of age and the power of eating right and working out as if every day were an audition for a Calvin Klein ad.

There is a price to be paid for believing your own hype.

“He probably went too hard,” said the Cats’ manager, Mike Marshall. “I tried to talk him out of it. I was going to give me a night off and have him manage. But he wanted to play. He was having fun and stroking the ball. Then his knee started hurting.”

Seek Franco and stumble into supporting evidence that baseball is harder to quit than a crazy girlfriend.

Meet the man who managed him this last time.

Marshall, most notably a former Los Angeles Dodgers first baseman, logged 11 major league seasons before retiring in 1991. What ever happened to him, anyway? He lounged around for a while, then spent 15 years managing independent teams from Illinois to California to New York to Arizona to Texas.

“The game usually calls you back,” Marshall said.

The amenities at this subterranean level of minor league ball are not quite what former major leaguers such as Marshall and Franco grew accustomed to. The clubhouse carpet is dirty, there is a slipcover on the couch in the center of the room and open jars of peanut butter in the reclaimed restaurant-style refrigerator by the door.

But there is always baseball, in one form or another, on the other side of that door.

“I’m kind of the Michael Corleone of independent league baseball — every time I try to leave, it brings me back,” Marshall laughed. “I’m kind of thinking, though, about the next chapter out of baseball. I think I’m going to write another chapter, maybe back to the golf course.”

As one 50-something former player ponders his exit strategy, another is beating at the door to get back in — although Franco could not pound on it with the Bunyanesque bat he waved over his head when with the Braves. They do not make telephone poles like that much anymore, not on short notice. He had to settle for something a little lighter and shorter, more fitting a man his age.

Franco’s considerable belief in his talents may have been massaged by the idea of becoming a five-decade professional player (he began in the minors in 1978).

He no doubt loved the idea of eliciting the kind of disbelief that met Cats infielder Chris Martinez when he called home to the Dominican to tell his people: Guess who I’m playing next to now?

“They didn’t believe me. They kept asking, ‘Are you serious? Are you serious?’” Martinez said.

But really, Franco said, this pass through lovely LaGrave Field, where the Trinity River bends just past the hand-turned scoreboard in center field, was not about resurrecting himself as a player. Oh, he still looked as fit as ever, even if the stubble atop his closely mowed head had gone snowy. There were motives at play over and above ego.

Playing for the Fort Worth Cats — putting up a five-game hitting streak before the knee started weighing him down, hitting .222 in 27 at-bats, with a double and an RBI at the age of 55 — was Franco’s idea of a gentle reminder:

Hello world, I’m still here, and I would like to manage one of your baseball teams one day.

“If you stay away, people forget about you,” Franco said.