Cody Bellinger, who damn near broke the Los Angeles Dodgers' home run record this season, managed only one home run as a high school senior. Alex Bregman, who belted 41 homers despite also leading his sport in walks, never once reached double-digit home runs in college. Mike Trout, on a faster home run pace for his career than all but four players, went deep every 49 at-bats in the minor leagues. Christian Yelich, who has required only 277 games to produce 80 home runs for the Milwaukee Brewers, was typecast as a slap hitter as he neared his mid-20s.

Major league baseball is immersed in the most prodigious home run era of its history, a remarkable circumstance for a sport once tainted by prevalent steroid use. Pitchers are throwing harder than ever and aggressive defensive shifts are commonplace, so hitters are looking to lift, looking to pull and, mostly, looking to slug. The 2019 season, dominated by theories about juiced baseballs, produced 6,776 home runs, blowing past the previous record of 6,105, set only two years earlier.

Bellinger, Bregman, Trout and Yelich are products of that environment. But they're more than that -- they're what happens when naturally gifted hitters evolve through a time defined by the long ball.

See, it's not that they couldn't hit home runs before; it's that they didn't care enough to. They were more concerned with the subtleties that produce great hitters, like controlling the strike zone, honing their opposite-field power and consistently meeting the baseball with the barrel of their bat. Their power wasn't yet prevalent enough for home runs to result from all that.

Bellinger, Bregman, Trout and Yelich are now four of the game's most complete hitters. They made up four of the top five spots in weighted runs created plus this past season, and on Thursday, they're each expected to finish in the top two in Most Valuable Player voting for their respective leagues.

What follows is a look at each player's path toward the most elusive part of his game -- the home run.

Cody Bellinger

Cody Bellinger was always young and always small for the level at which he played. He was already scrawny before growing 8 inches during his junior year of high school, shooting from 5-foot-8 to 6-foot-4. When the Dodgers made him their fourth-round pick in 2013, he weighed no more than 165 pounds. His frame was expanding too quickly. His metabolism was working too efficiently.

"He would eat and eat and eat, and he would never gain," Bellinger's father, Clay, said. "That's just the way it was -- it's genetics."

Clay, a former utility player who spent three seasons with the New York Yankees, could relate. He had the same body type when he graduated high school, then added weight later and grew stronger. He knew the same would happen for his son, and that with it, the power would ultimately emerge; those line drives Bellinger kept sending into the outfield gaps would begin to travel over the fence with more frequency. But watching his son become one of baseball's most celebrated home run hitters was unimaginable.

"When you're hitting one in Little League, when you're hitting one in club ball, when you're hitting one in high school, it's kind of hard to envision that," Clay said.

Bellinger hit one home run in his final season at Hamilton High School in Chandler, Arizona, and didn't produce many more than that in other settings. He was almost always the best player on the field but was hardly ever the strongest. Teammates would tease him about not hitting home runs, but Bellinger seemed content. His hand-eye coordination was elite, his mechanics were uncommonly sound. He hit line drives all over the field and hardly ever chased pitches outside of the strike zone.

"If he wanted to, he probably could've hit more home runs," Clay said. "But I think it would've taken away from everything else he was doing."

Bellinger managed only four home runs in the 98 games he spent at the Dodgers' Rookie-level affiliates in 2013 and '14. The following year, the home runs came suddenly and frequently. Bellinger blasted 30 in 128 games for Rancho Cucamonga in 2015, then 26 in 117 games -- with far fewer strikeouts -- in Double-A and Triple-A in 2016. That was followed by 111 home runs in 450 major league games from 2017 to 2019, a mark topped by only five players during that stretch.

Bellinger at one point decided to consume an entire gallon of milk each day, working most of it into protein shakes. It helped him gain about 20 pounds over the course of one minor league offseason. In hopes of unlocking his power, the Dodgers altered Bellinger's mechanics, incorporating a hand pump that was followed by a flatter bat angle, as detailed by The Athletic.

Bellinger still struggles to keep weight on, losing at least 10 pounds over the course of a season. He constantly alters the position of his hands to get into the right firing position, sometimes multiple times within the same game. At 24, he is already among the game's best all-around players. But he remains a work in progress.

"I always thought that when he ever did get to the big leagues, he was going to hit .300 with 100 walks," Clay said. "Now he's finally hit .300, and I think he can do a whole lot better."

Alex Bregman

Paul Mainieri was coming back from delivering a speech downtown. It was 10 o'clock at night. LSU's baseball stadium was visible on the drive home. His wife turned to him and asked why the lights were on. Mainieri, the Tigers' head coach, already knew the answer. It was Alex Bregman, who had probably convinced one of the student managers to open the gate, turn on the lights and hit him ground balls again. Mainieri confirmed his assumption the following morning and finally gave in, presenting Bregman with a key to the facility.

It was a favor to everybody.

"I've never had a player, in 38 years of coaching, that I could compare to Alex as far as his love of the game, his work ethic, just how much he put into it every day," said Mainieri, who has spent the last 13 years running LSU's baseball program. "You could just see that he had greatness written all over him because he was not going to allow himself to fail."

Bregman's size -- 6 feet, 180 pounds -- has hardly changed at all since he arrived on LSU's campus six years ago, when major league scouts projected him as a catcher. His emergence as a home run hitter has nothing to do with growing into his body; it's the result of an obsessive work ethic that augmented an elite skill set.

Bregman batted .337/.409/.514 and was a two-time All-America shortstop in three seasons at LSU, but he managed only 21 home runs in 196 games. He had the bat speed and hand-eye coordination to smoke line drives all over the field and the strike-zone recognition and two-strike approach to walk more often than he struck out. But home runs were elusive.

"It's just that to hit home runs you have to elevate the ball, and he didn't do that as much in college," Mainieri said. "But he hit the ball just as hard in college as he is in the major leagues."

Bregman played in 132 games over the college season and both of the Houston Astros' Class A levels in 2015 and managed only 13 home runs. He then played in 129 games in Double-A, Triple-A and the major leagues in 2016 and increased his home run total to 28. As a full-time major leaguer from 2017 to 2019, his home runs went from 19 to 31 to 41.

"I thought that he had more power in there and eventually it would show up," Mainieri said. "But I never could've predicted that he would be a 40-home-run-a-year guy."

Bregman has, like many others, altered his approach as a professional. He has actively tried to avoid ground balls, has pushed his hands back and has scrapped an inside-out swing for one that stays through the zone as long as possible, as outlined by FanGraphs. But he still rarely chases -- Bregman swung at 15.5% of pitches outside the strike zone this season, the lowest rate in the majors -- and his home run power isn't as pronounced as one might think.

Bregman's average home run distance in 2019 was 382 feet, which ranked 422nd among the 466 players with at least 50 batted balls, according to Statcast. The inflated home run total was the result of a home ballpark with a short left-field fence, in an era when balls are flying out like never before, from a player who refuses to be denied.

"You take a really good hitter like Alex and put him in an environment where more home runs are hit and he's gonna hit home runs," Mainieri said.

Mike Trout

Most everyone seems to recall the first time they saw Mike Trout play in vivid detail, and Abe Flores is no exception. It was at the Los Angeles Angels' minor league facility in Tempe, Arizona, in 2009. Trout was 17 and playing for the organization's Rookie-level affiliate. Flores sat in the bleachers with a stopwatch in hand. He saw Trout hit a chopper to the left side and turn it into an infield single.

"Oh my god," Flores said to himself.

He couldn't believe a kid who was already so big and strong also possessed that level of burst and speed. Flores spent 10 years with the Angels, the last four as director of player development from 2008 to 2011, a stretch that coincided with Trout's rapid ascent through the minor leagues. Flores loved watching the simple act of Trout running first to third on singles but was also in awe of his tools as a hitter -- the strike-zone discipline, the rapid hands, the way baseballs jumped off his bat.

But the power still was untapped.

Trout was built like a linebacker when he joined the Angels out of high school, but his swing traveled through a steep, downward path that resulted in too many ground balls, as mentioned by The Ringer a couple of years ago. He could often pull pitches with authority, but he lacked power the other way because of another flaw in his swing: Trout would get inside of pitches and "carve" them to right field, producing batted balls that seemed to drift as opposed to traveling on a line with backspin.

Trout slashed .341/.426/.516 in the minors but homered only 23 times in 290 games. Over time, however, Trout got his swing into a more conventional plane, staying through the zone for a longer period and adding more loft to his finish. By 2011, he homered 11 times in 91 games for Double-A Arkansas, which plays in what is historically a pitcher-friendly park. Then he reached the major leagues for good and quickly became a ferocious slugger, in addition to so much else. His 285 career home runs stand as the fifth most in history through a player's age-27 season.

"He was a really special guy, even as a young player," said Flores, who scouted for the Yankees and the Minnesota Twins after leaving the Angels. "And when you got next to him, how big and strong he was, how physical he was -- you knew the power would come."

Trout took pitches until he got a strike throughout his minor league career -- not because anybody instructed him to, but because he believed it was important to build a deep catalog of pitches. When he reached the majors, he possessed an advanced feel for his strike zone, in addition to all the other gifts that were destined to make him an elite hitter.

Trout's isolated power, which measures raw power through the amount of times someone hits for extra bases, has gone from .238 to .353 in eight major league seasons. In 2019, Trout averaged 419 feet on his home runs and ranked fourth in barrels per plate appearance, according to Statcast.

"I think the parallels between Mike and other players is that power is the last component that blossoms," Flores said. "That comes. The more concerns are the ability to make consistent contact, understanding the strike zone, making consistent hard contact, and then the power will blossom in the end."

Christian Yelich

There's something about the fluid swing of a graceful left-handed hitter that makes baseball people swoon. It's the easy rhythm, the natural flow, the seemingly effortless power, an artistry that appeals to the senses like nothing else in the sport.

Christian Yelich had this in abundance. The home run power was elusive early on, but sometimes he'd deliver the barrel right on time, and all the other components would fall into place, and he'd send a baseball sailing over the center-field batter's eye at Roger Dean Stadium, where the Marlins' Rookie and Class A teams play. That's when Dan Jennings' imagination would run wild.

"You'd look at that body," Jennings said, "and you'd go, 'How the hell does he do that?'"

Jennings, now a front-office assistant for the Washington Nationals, worked for the Marlins from 2002 to 2015, occupying a variety of roles that included general manager and interim manager.

When the Marlins made Yelich a first-round pick out of high school in 2010, Jennings envisioned someone who would win multiple batting titles and hit 20 to 30 home runs in the major leagues. Yelich's hand-eye coordination was among the best Jennings had ever seen. He was long and lanky and flat-chested -- "He was the guy that had the long muscles," Jennings said -- but he was bursting with quick-twitch, and occasionally the power appeared.

"He always hit a lot of doubles," Jennings said. "You knew ultimately those doubles would turn into home runs."

Yelich managed only 37 home runs in 309 career minor league games, then hit 16 in 270 major league games in 2014 and '15. Over the next two years, he produced 39 home runs. The two after that, with the Brewers in 2018 and 2019, resulted in more than double that total -- 80 homers, including 44 this season even though he was limited to 130 games because of injury.

Over time, Yelich came to embody the evolution of the modern hitter, sending more pitches to his pull side while increasing the percentage of fly balls. In the summer of 2018, he began standing more upright, with his hands higher and his shoulders more square, getting out in front of pitches as opposed to letting them travel deep into the strike zone, a development that was detailed in ESPN's Body Issue.

But the key to everything, Jennings said, was consistently "hitting against a stiff front side," which involved Yelich locking his right knee at the point of contact, creating the necessary leverage. Everything else was about individual comfort.

"He has a gift," Jennings said. "I mean, one day God decided to make a hitter and he made Christian Yelich. The rest of it was gonna come from his hard work and him understanding his swing and unlocking the rest of it. He's done it. He's a gifted, gifted athlete, he's a blessed hitter, and he worked really hard to get the rest of it to become usable for power."

Yelich appeared in a popular MLB commercial that aired in March. It involved a mock news conference with all of the game's biggest stars making increasingly more audacious predictions about the upcoming season. At one point, Yelich proclaimed: "I'm gonna hit 50 home runs this year."

Jennings saw it and laughed.

"It's one of those statements that make you go, 'What the hell,'" Jennings said. "And sure enough, he comes in and he almost does it."