It may be hard to remember that Ronald Acuña Jr., the Atlanta Braves’ slugging sensation and a front-runner to win this year’s National League Rookie of the Year Award, was not even ranked among the team’s top prospects just a few years ago.
A native of Venezuela from a baseball crazy family, he signed a contract with a $100,000 bonus, which was well below what the top international prospects received. He was 16 years old, raw, 5-foot-10 and 160 pounds.
But a year later, in 2015, his best traits — his quick bat and hitting ability — stood out to Braves coaches watching him in an off-season league.
“We watched three days of games after we had meetings in the morning,” Kevin Seitzer, the Atlanta Braves’ hitting coach, said. “And the at-bats he had, his pitch recognition, his grinding with two strikes — it was just one of those things whereyou go: ‘Oh my gosh. Wow.’”
Since he made his major league debut on April 25, Acuña, a left fielder, has been one of baseball’s hottest hitters and shaken up an often tired game with his youthful exuberance. He has torn through opposing pitchers like an experienced hitter and helped propel the rebuilt Braves to their first National League East title since 2013. They will begin an N.L. division playoff series against the Los Angeles Dodgers on Thursday night.
In 111 games this season, Acuña hit .293, with 16 stolen bases and a .917 on-base plus slugging percentage, narrowly trailing outfielder Juan Soto, 19, of the Washington Nationals, his closest competition for the Rookie of the Year Award. He is one of five players in history to hit at least 26 home runs before turning 21. In a stretch in August, he became the youngest player to hit a home run in five consecutive games.
During that run, he was at the center of one of the season’s biggest controversies, over baseball’s unwritten rules. Having hit a leadoff home run in three previous games, he stepped to the plate in the first inning against José Ureña of the Miami Marlins. In what appeared to be a deliberate attempt to slow him down, Ureña hit Acuña’s elbow with a fastball, forcing him out of the game, emptying both benches, and earning a six-game suspension.
Acuña, 20, has kept hitting, though, and may have had the last laugh. He is shown celebrating a home run against the Marlins in a new M.L.B. television ad called “Let the Kids Play” that pushes back against the perceived stodginess of the game.
Acuña said he was just being himself, with his play and personality.
“I always dreamed of reaching the big leagues and having a good season, and thank God it’s happening,” Acuña said in a brief interview in Spanish. “I always expected this of myself.”
The passion for baseball in Venezuela runs deep, and Acuña grew up around baseball players. His father, Ronald Sr., 39, played eight years in the minor leagues, most of them with the Mets, and four years professionally in Venezuela. Because his father had him at a young age, Acuña grew up watching his father play in the United States and Venezuela.
The baseball bloodline does not end there. Acuña’s younger brother, Luisangel, 16, a shortstop, signed for $425,000 with the Texas Rangers in July. Their uncle José Escobar played briefly in the major leagues for the Cleveland Indians in 1991. And several cousins, including pitcher Kelvim Escobar of the Toronto Blue Jays and shortstop Alcides Escobar of the Kansas City Royals, have played in the major leagues as well.
“As a kid, I always played baseball,” Acuña said. “But as I grew up, I realized I could be a baseball player just like them.”
Playing against older competition, Acuña rocketed through the minor leagues with the Braves. He has put on muscle and height; he is now 6 feet. Once unranked, he was considered the No. 1 prospect in all of the minor leagues before this season.
“At 20, I was still in college,” Braves catcher Kurt Suzuki said. “It’s pretty incredible what he’s doing now. The passion, the energy, the talent are all undeniable.”
Acuña really took off after the All-Star break. By then he was hitting .249 with seven home runs but also flaws in his swing that had not been exposed against lesser talent in the minor leagues. Seitzer suggested small changes to the positioning of Acuña’s hands and reminded him to relax.
Acuña incorporated the changes. In the second half of the season, the Braves, already among the N.L.’s best offenses, moved him to the leadoff spot, and neither has been the same. The Braves soon regained control of the division lead. Acuña smashed 19 home runs and posted a 1.028 O.P.S. in the second half.
“Ronald is a special player,” said Ender Inciarte, the Braves’ center fielder and a fellow Venezuelan. “He’s very different. At 20 years old, I can probably count on one hand the players that can do what he’s doing.”
“What has impressed me the most about Ronald is his ability to learn,” he added. “He’s shown he can mature and learn with the league, and he’s made the needed adjustments quickly.”
Acuña has made a difference not just with his productivity. After three short-lived playoff appearances from 2010 to 2013, the Braves reshaped their roster by acquiring younger talent through trades and the international market. But because of several signing infractions, the general manager then, John Coppolella, lost his job and was barred by Major League Baseball last year. The Braves lost 13 prospects and received other penalties.
Still, those young players, including second baseman Ozzie Albies, 21, starting pitcher Mike Foltynewicz, 26, third baseman Johan Camargo, 24, and Acuña — combined with veteran stalwarts — have energized the Braves. During games, Acuña is often seen laughing or joking with his close friend Albies, among others.
“They help me, this old guy,” Braves Manager Brian Snitker said. “Their energy and emotion and how they play the game is infectious to all of us. It does a lot for everybody on the club.”
Since Acuña was Albies’s teammate in the minor leagues, the two had talked often about reaching the majors together and doing exactly what is happening now. Albies said he admired Acuña’s confidence at such a young age.
“We always dreamed of having good season, staying healthy, reaching the playoffs and reaching the World Series, because that’s what everyone wants,” Acuña said. “Thankfully, that’s what we’re doing.”