For Bernie Williams, grabbing a bat was easy. He would pull out the same trusty 34 1/2-inch, 33-ounce Rawlings model for all occasions during his New York Yankees career, whether that was in spring training or the playoffs, whether he was facing a flamethrower or a knuckleballer.

Music, however, is different.

“Choosing a guitar is about the gig,’’ Williams said. “It’s about the sound that you want to create, and it’s about the music that you’re going to play. You need the right instrument with the right gig, and that varies with time.”

Such is what vexes the former outfielder as he prepares for a second big-league debut — this time in the arts. Williams for the first time will play guitar with the New York Philharmonic, at the Spring Gala on Wednesday, an epic milestone for a five-time All-Star and four-time World Series champion now deep into life’s second act.

So, which guitar? The acoustic steel string? The archtop? Williams said a few weeks ago that he might even choose to go electric “for that sort of Santana-like sound,” though he added it “might just be too over the top for that environment.”

Williams, who spent his entire career with the Yankees from 1991 to 2006, has rebranded himself as an accomplished musician, ordained with a Latin Grammy nomination and critical acclaim. Still, at age 55, the thought of stepping into the spotlight at another hallowed New York venue — think Yankee Stadium, but with better acoustics — gives Williams butterflies.

On Wednesday, he will play one selection, his 2009 piece “Moving Forward,” as newly arranged by jazz artist Jeff Tyzik. Famed conductor Gustavo Dudamel will be at the helm.

“I expect to be as nervous as I’ve ever been on any kind of stage,’’ Williams said “But I think it’s gonna be no different from playing a seventh game of the World Series, you know?”

To answer that last question: No, Mr. Williams, we don’t know. There is no one else in baseball history poised to compare the experience of baseball’s Fall Classic and the Philharmonic’s Spring Gala. No one else has played in “The House That Ruth Built” and in the concert hall Leonard Bernstein christened by conducting on opening night in 1962.

Williams’ distinction means much gnashing of teeth for the president and CEO of the New York Philharmonic. Gary Ginstling is an ardent Mets fan.

“This is a deeply difficult decision for me, I have to say,’’ Ginstling cracked during a phone interview. “I did scour the landscape for any retired Mets. But no one could hold a candle to Bernie Williams.”

This experience is enough to give Williams flashbacks to his first big-league at-bat. The switch hitter was 22 years old when he stepped to the plate in the third inning at Yankee Stadium against left-handed junkballer Jeff Ballard on July 7, 1991. It was hardly a soaring opening note. The Baseball-Reference box score immortalized the moment this way: Groundout: 3B-1B (Weak 3B).

The outing got better. Williams drove in a run with the sacrifice fly in the fifth and brought home another run with an infield single in the ninth.

“I remember being really nervous,’’ Williams said of that debut. “I remember being in this place where there was a lot of uncertainty about my career and my own ability to stay in the big leagues. All I wanted to do was to get an opportunity to be able to show people what I can do.’’

A week later, Williams hit his first home run at Anaheim Stadium against the California Angels. He hit a fastball thrown by Chuck Finley over the left-center field wall. He kept rolling from there: a .297 batting average with 287 home runs and 147 stolen bases over 16 seasons.

July 14, 1991
Bernie Williams hits his first career home run pic.twitter.com/nYIteNuXlL

— NY Yankees Throwbacks (@yankeethrowback) February 19, 2022

Williams helped the Yankees win four World Series titles, including three in a row from 1998 to 2000. His 22 career postseason homers rank third all-time behind Manny Ramírez (29) and José Altuve (27).

That summation has applied, at times, to his musical career, partly because it would be easy to dismiss Williams as just another retired jock with an expensive new hobby. But his lifelong musical journey is part of what appeals to the New York Philharmonic. The Spring Gala, to be performed at the David Geffen Hall at the Lincoln Center for the Performing Arts, is a fundraiser for musical education. Ginstling wants the younger crowd to be inspired by Williams’ scholarly dedication to his craft.

Williams’ first instructor was his father. Bernabé Williams, an able seaman with the Merchant Marine, returned from Spain with a gift for his 7-year-old son. It was a guitar that his son never put down. The family then found a guitar teacher in its neighborhood in Puerto Rico, and by the time Bernie was 9 years old, he had performed on a local radio station with other star pupils.

“The guitar teacher had all the little kids that were taking lessons with him, the ones that were kind of like standouts,’’ Williams recalled. “He would give them an opportunity to play a song or two on that radio show. … It was such a great experience and kind of set the stage for everything that came after.”

Williams kept playing throughout his baseball career, especially so while grieving the loss of his father, who died of lung disease in 2001. The former batting champion then studied guitar and composition for a year at the State University of New York at Purchase in preparation for his first album, “Moving Forward.” That release strengthened his bona fides thanks to 14 solid tracks including collaborations with Bruce Springsteen, Jon Secada and Dave Koz.

Bernie Williams and musician Jon Secada performing during the Grammy SoundCheck on April 17, 2009, in New York City. (Joe Kohen / WireImage)

But eventually, Williams formalized his expertise. He enrolled in the prestigious Manhattan School of Music en route to a bachelor’s degree.

“I tell you what, none of the home runs that I hit in the postseason helped me there,” Williams said. “I had to really reinvent myself. And in a very strange way, I had to earn the admiration of the kids that I was playing with, because they were all virtuosos in their own instruments by the time they got to the Manhattan School of Music.

“I was the old guy in the back of the room. I was asking all the questions and asking that no one erase the blackboard until I was finished writing all the notes.”

Williams wasn’t chasing a diploma for the sake of the paper. The experience signified his graduation from ballplayer to artist.

“I think the school gave me a great perspective on the reasons why I wanted to be a musician and the responsibility that we have as music makers to make sure that we make this world a better place,” he said. “The joy and the power of music is just incredible thing to use for the good of the world.”

Therein lies the message of the Spring Gala and underscores why even a Mets fan like Ginstling embraces a Yankee in the house. The eclectic bill on Wednesday is designed to introduce new audiences to the philharmonic. Selections range from a suite from Richard Strauss’ “Der Rosenkavalier” to two pieces from rapper Common to an aria called “Bachianas Brasileiras No. 5,” sung by the South Korean soprano Hera Hyesang Park.

“I think that’s what I’m so excited about,” Ginstling said. “We’re gonna get a ton of Bernie Williams fans in the house that night who probably will be hearing the New York Philharmonic for the first time. It’ll be great for them to hear Bernie, but we want them to hear the orchestra play Strauss. And we want them to hear the orchestra play Nina Shekhar, this up-and-coming composer whose piece we’re playing.

“We’re hoping that they’ll get hooked not just by Bernie, but by all of this repertoire, and they’ll come back.”

Until then, Williams sometimes wakes up unexpectedly at 2:30 a.m. and reaches for his guitar. Still half-awake, he’ll strum until the notes sound just as they should before allowing himself to drift back to sleep.

“That’s the level of preparation you need for an event like this,” he said. “Because when the nerves come in, you want to still be in control and not freeze when the situation arises. The only antidote to that is being well-prepared.

“That’s true of doing anything that requires the spotlight and great expectations and great pressures.”

Williams hardly is the first ballplayer to make news with his music. As far back as 1964, a Yankees bus ride turned tense when Yogi Berra grew tired of hearing “Mary Had a Little Lamb” as played on the harmonica by a utility infielder named Phil Linz.

But that was the “New York Phil harmonica.” The New York Philharmonic is a whole different ballgame.

“If anything,” Williams said, “baseball taught me to be able to perform under pressure, and this is definitely going put that to the test.”

(Top photo: Mychal Watts / Getty Images)