Joey Gallo debuted for the Rangers on June 2, 2015, and got a single in his first career at-bat, a first-inning base hit off Jeff Samardzija, then of the White Sox. What's notable about that is that over the course of his career Gallo has become famous for not hitting singles, but rather home runs. Lots of them.

He doesn’t just hit homers, though. He hits them at a disproportionate rate compared to all other kinds of hits. Appropriately, he hit his first career dinger in his next at-bat in his debut, and has kept on hitting them. And although he’s frequently compared to hulking sluggers known for home runs, strikeouts and walks (a.k.a. "three true outcomes"), such as Adam Dunn, Rob Deer and Chris Davis, Gallo's performance is on its own level.

In fact, when Gallo hit his 100th career home run on Wednesday against the Pirates, he became the first player in Major League history to reach 100 home runs before 100 singles, according to the Elias Sports Bureau. Let’s take a look at that and the other ways that Gallo has redefined what it means to be an extreme slugger in 2019.

Homers? Yes. Singles? Not so much.

Gallo has 93 career singles, by far the fewest by any player at the time of his 100th career home run. No player had ever reached 100 home runs before 100 singles, and none had even had fewer than 172 singles at the time of that 100th career HR.

Fewest career singles at time of 100th HR

1. Joey Gallo: 93
2. Russell Branyan: 172
3. Ken Phelps: 174
4. Ryan Howard: 176
5. Chris Carter: 179
6. Dave Kingman: 180

You read that right, Branyan was first on this list until Gallo came along, and he had almost twice as many singles as Gallo when he got to 100 homers. (And in case you were curious, Gallo got to 50 homers before 50 singles, too. He hit his 50th home run on April 3, 2018, in his 204th career game. His 50th single didn’t come until April 9, in career game number 210.)

Not only did Gallo become the first player whose homers won the race with singles to 100, he reached 100 home runs in just the third-fewest games in Major League history.

Fewest career games to 100 HR

1. Ryan Howard: 325
2. Ralph Kiner: 376
3. Joey Gallo: 377
   4-T) Chuck Klein: 390
   4-T) Bob Horner: 390
4. Mark McGwire: 393

Just how extreme is Gallo’s singles total for his career? Again, he has 93**,** and he entered the season with more than 1,300 career plate appearances**.** In 2018, there were 59 players who hit at least 93 singles for the season. The leader was Jean Segura, who hit 136.

Here’s how Gallo’s singles-to-home-runs breakdown has looked each year of his career:

2019: 12 HR, 11 singles
2018: 40 HR, 38 singles
2017: 41 HR, 32 singles
2016: 1 HR, 0 singles (1 HR was only hit of season)
2015: 6 HR, 12 singles

He’s completed three seasons with more homers than singles, in each of the previous three years. The only position player with more seasons with at least one home run and more homers than singles is Mark McGwire, who had four such seasons. The only other player with three such seasons is Ryan Schimpf.

But that 2016 season is, of course, a bit misleading -- since he played just 17 games, got 30 plate appearances, and mustered one hit, a homer. Let’s look at seasons with 20 or more home runs instead. If we look at those, Gallo has two such seasons -- with more homers than singles -- which is second-most in Major League history behind McGwire’s four.

20-HR seasons with more HR than singles:

1. Mark McGwire: 4
2. Joey Gallo: 2
   T-3) Matt Olson: 1
   T-3) Ryan Schimpf: 1
   T-3) Barry Bonds: 1

And if we up it to 40 homers, which Gallo achieved in each of the last two years, it gets even more rare. Before 2017, there had been three seasons in Major League history where a player had 40-plus homers and hit fewer singles than homers: two by McGwire and one by Barry Bonds. Since then, Gallo has done this twice.

He’s got the power

It’s not just that Gallo hits all of these homers, and so few singles, it’s how he hits the home runs. Gallo has hit six home runs this season with an exit velocity of 110 mph or more, second-most in the Majors behind Gary Sanchez.

His 96.7 average exit velocity on all kinds of batted balls entering Wednesday is highest among hitters with at least 50 batted balls this season -- by more than a mile and a half per hour. Carlos Santana and Nelson Cruz are tied for second at 94.9 mph. Gallo entered the day with a 13.7 barrels per plate appearance rate, which is third to Sanchez and Jose Abreu.

It’s still early in the season, but he’s outpacing himself in many of these categories, too. His highest average exit velocity for a full season was 93.9 mph last year. He has a 57.4 percent hard-hit rate this season. His career best is 52.2 percent in 2017.

And he’s making adjustments

In the first month-plus of the season, it appears Gallo has made some adjustments as well. Gallo entered Wednesday's game hitting .269 on the year. Not necessarily anything to write home about, until you consider this: Gallo’s batting averages in his career? .204 in 2015, .040 in 2016 (17 games), .209 in 2017 and .206 in 2018. This is new for him.

In fact, this is the first season where he’s had a batting average above .250 through 15 or more games played in a season. He’s been hitting above .250 since he completed his 17th game this year, on April 20. Wednesday was his 31st game this season.

How is Gallo doing it? A few things stand out. First off, he’s chasing the ball less -- with a 19.0 percent chase rate entering Wednesday**.** 205 batters have seen at least 200 out-of-zone pitches including Gallo, and that 19.0 percent rate is tied for 22nd-lowest. Last year, Gallo had a 29.2 percent chase rate, which ranked tied for 132nd of 226 batters to see at least 750 out-of-zone pitches for the year. His 10.2 percentage point improvement in chase rate is the second-best among hitters to see at least 750 out-of-zone pitches in 2018 and 100 in 2019.

Some other evidence that perhaps he’s honing in on his swings: he has a 27.5 percent first-pitch swing rate entering Wednesday, which ranks tied for 148th-lowest of 317 batters with at least 50 plate appearances. Not exactly league-leading, but also not the highest rate in the league, or even in the top 10. Last year, 144 batters had at least 500 plate appearances, and the only ones with first-pitch swing rates higher than Gallo’s 41.4 percent were Javier Baez, Freddie Freeman, Ozzie Albies, Jose Altuve and Nicholas Castellanos. At least to start off, Gallo is waiting for his pitch.

He’s whiffing on just about the same percentage of swings, but when there are fewer swings involved, that’s fewer countable whiffs. And what does that mean? More contact made overall -- or maybe just more patience. Gallo’s walk rate is 19.8 percent this season entering Wednesday. While that can be attributed in part to the state of the Rangers’ offense, he could be turning those into strikeouts, but he isn’t. Instead, he’s walking in 19.8 percent of his plate appearances. The only batter who’s walking more frequently is Mike Trout, in 23.4 percent of his plate appearances.

Gallo’s walk rate is up from 12.8 percent last year, and his strikeout rate is just slightly down -- to 33.6 percent from 35.9 percent last year. That, combined with his home runs, means that his three true outcomes percentage is actually higher than what it finished at in each of the last two seasons. He’s homered, walked or struck out in 61.8 percent of his plate appearances. He had a 55.6 rate for the year last season. In other words, he’s still Joey Gallo -- he’s just doing it a bit differently.