Entertainment

Tapping into baseball & B’way lore

Imagine owning a home plate that once graced the old Yankee Stadium. Or the glove worn by the player who ended Joe DiMaggio’s 56-game hitting streak with a catch. Or the letter Babe Ruth wrote to his mistress, warning her to stay away from his hotel because his wife was there.

Al Tapper doesn’t have to. They’re all in his apartment.

And you came this close to seeing it.

Tapper, who composed the music for off-Broadway’s baseball-themed “National Pastime,” planned to display his collection in the theater’s lobby.

Turned out, it would cost more than $10,000 to insure it.

So, strike that. But he did give The Post a private tour.

Even Tapper’s penthouse is historic. Occupying an entire floor of a Midtown hotel, it used to be four apartments, two of them once rented by composer Richard Rodgers and writer Edna Ferber, who were neighbors there in the ’30s.

Even at 70, Tapper displays a childlike enthusiasm when showing off his treasures. Some are even accompanied by visual aids: Next to the polo cap once owned by Ruth, a tiny video screen shows a scene from the classic Harold Lloyd silent comedy “Speedy,” in which Ruth is seen wearing it.

It’s a collection that wouldn’t be out of place at the Baseball Hall of Fame. In fact, one of Tapper’s treasures — the cap worn by New York Giants outfielder Bobby Thomson when he hit “The Shot Heard ’Round the World” in 1951 — was there for decades until it came up for auction, where Tapper snatched it up.

His most prized possession? The cleats Ted Williams wore in his final game.

“Williams was my childhood hero,” the Boston native says. “When I was a college freshman, I went to his last game. He hit a home run in his last time at bat. He ran around the bases and never came out again. Everybody wondered whether he would come out to take a bow. But gods don’t make curtain calls.”

Tapper — who stopped dating a woman once he realized she had no idea who Jackie Robinson was — doesn’t confine his collection to baseball. He also owns a sweater worn by Gene Kelly in “Singin’ in the Rain,” a movie script featuring handwritten notes by Marilyn Monroe and a letter written by Mario Puzo to Marlon Brando that begins: “Dear Mr. Brando, I wrote a book called ‘The Godfather,’ which is having some success.”

Needless to say, these sorts of things don’t come cheap. And while Tapper’s done well as a theater composer (“Sessions,” “An Evening at the Carlyle”), he spent 30 years as a venture capitalist. He retired in 1998.

“I’ve done nothing but write ever since,” he says. “And I’ve never been happier.”

His latest effort, “National Pastime,” is a comic musical about a Depression-era radio station that tries to drum up listeners by broadcasting games featuring a made-up team that’s forever on the road. It was originally written as a one-act play by his friend and collaborator, Tony Sportiello.

The musical version, which bowed a couple of years ago at the Baseball Hall of Fame in Cooperstown, is now getting the theater version of what baseball considers a “tryout”: playing the Peter Jay Sharp Theater, possibly en route to Broadway, the Big Leagues.

“It’s something I wanted to do since I was 10 years old,” Tapper says of his Broadway ambitions. “Either that or play center field for the Red Sox.

“But I don’t think they’re going to give me a tryout.”

“National Pastime” plays the Peter Jay Sharp Theater, 416 W. 42nd St., through Aug. 25; 212-279-4200.