Walk-up music -- the unofficial soundtrack of the baseball season -- didn't begin with the Philadelphia Phillies in 1994. But longtime Philadelphia publicity director John Brazer's "Lenny Dykstra" moment is an interesting marker on MLB's musical timeline. Brazer was responsible for the music played during games at Veterans Stadium. He simply played the music he liked, such as the Allman Brothers, Warren Zevon, the Rolling Stones and REM, between innings.

Then, one day, Dykstra called Brazer out to the outfield during batting practice to talk about something very important.

"The Dude looks at me and says, 'Dude, we have to change some things up,'" Brazer recalls. "I said, 'OK.' But I still didn't know what he was talking about. He said, 'When I come up to bat for the first time, I want you to play Hootie and the Blowfish's 'Hold My Hand.'"

Brazer nodded and asked if that was all Dykstra wanted.

"No, dude," Dykstra replied. "The second time I come up to bat, I want you to play Tom Petty's 'Won't Back Down.'"

Brazer said OK, and asked what Dykstra wanted played before his third at-bat. Dykstra thought about it for a while and then replied, "I liked that song you played a couple days ago -- 'Philadelphia Freedom' by Elton John."

And when Dykstra batted a fourth time? The Dude thought about it some more and decided that Brazer could play whichever previous song had led up to a hit.

Dykstra, however, did not get a hit to any of those songs. Instead, Brazer remembers, The Dude went 0-for-8 over the next two games, thus ending his walk-up music experiment, at least temporarily.

So if Dykstra doesn't get credit for turning the batter's box into a jukebox, who does? In 1993, the Seattle Mariners might have been the first club to start playing songs for every player. But, unlike nowadays, the team selected the music, not the player. And the M's usually chose songs that fans could easily associate with their players, says marketing director Kevin Martinez.

For instance, since Jay Buhner's nickname was Bone, the Mariners played "Bad to the Bone" when he batted. Catcher Dan Wilson was known to Seattle fans as "Dan the Man," so the team played "What a Man" before his plate appearances. Reliever Mike Jackson strode in from the bullpen to the ominous strains of Michael Jackson's "Thriller." Raul Ibanez got "Werewolves of London" because of the chorus that sounds like "Ra-oooollllll!!!"

Drake tops the chart of most popular MLB walk-up music artists, appearing 17 separate times as a lead artist (not to mention an additional 13 as a featured act). Bob Levey/Getty Images

And catcher Dave Valle sometimes got stuck with the theme song to the 1960s TV show, "The Big Valley."

"It was great if there was a piece of music that matched their personality or their name," Martinez says. "If it had some meaning or had some connection for the fan between the music and the player, it had a little more impact than just a cool song that was popular at the time."

Few song-player pairings are more memorable than erratic (and, alas, fictional) Indians closer Ricky Vaughn's theatrical entrance to games accompanied by "Wild Thing" in the 1989 movie "Major League." Vaughn, played by actor Charlie Sheen, helped make entrance songs popular for pitchers, especially closers.

In the 1970s, Pittsburgh's organist played snake-charmer music whenever Dave (Cobra) Parker batted. And former Cardinals organist Ernie Hays, who retired after 40 years on the job in 2010, told a St. Louis radio station that Lou Brock requested that the theme to the movie "Shaft" be played when he batted.

Who knows? Perhaps walk-up music goes back even further. Maybe Babe Ruth had a banjo player strum "Yes Sir, That's My Baby" when he batted in the 1920s.

While the origins of walk-up music are obscure, what is certain is that it is now as intrinsic a part of baseball's fabric as $150 replica jerseys. Every player now strides to the plate (or mound) accompanied by his own personal anthem, with tunes ranging from rap, pop and heavy metal to country and even Frank Sinatra (more on that later). Well, not quite every player. Earlier this season, Oakland second baseman Tyler Ladendorf specifically requested that the Athletics not play music for his at-bats.

But for most everyone else, walk-up music is as crucial and identifiable as the names and numbers on their jerseys.

"Your walk-up music has to mean something," says Minnesota Twins outfielder Torii Hunter, whose most-played walk-up song over his 17-year career is the 2013 hip-hop ditty "Immortal" by Kid Cudi. "When you hear the song's lyrics, you want it to kind of lock you in before you go to the plate. So I have to hear those words: 'I've got my lion heart ... flowing through my brain.' And when I step to the plate and I hear, 'Tonight I feel immortal,' I just feel unstoppable.

"When you choose a walk-up song, you've got to choose wisely."

Just ask Cody Decker. Decker, a catcher in the Padres' system, picked Foreigner's "Jukebox Hero" as his walk-up music last season because he liked the chorus.

"But hearing that four times a night, for a month ...?" he says. "I used to like Foreigner but now I hate that song. It nauseates me."