This 20-year-old is quickly blossoming into a star

The Brewers are well on their way to winning the NL Central for the second straight season and third time in the last four years.

There has been no shortage of talented players leading the way, whether it’s William Contreras, Willy Adames or Freddy Peralta, but the club’s biggest development has been the emergence of 20-year-old Jackson Chourio.

Ranked as MLB Pipeline’s No. 2 overall prospect entering the season, Chourio inked a record-setting contract last offseason and came into Opening Day starting in Milwaukee's outfield. After struggling through his first 50 games, Chourio has gone bonkers for the last three months and filled the void left by Christian Yelich and his season-ending injury.

Chourio is hitting .276/.331/.467 with a 120 wRC+ and 3.4 Wins Above Replacement (FanGraphs) across 128 games, all while playing excellent outfield defense. He also has been a true power-speed threat with 19 home runs and 20 stolen bases. With his next home run, Chourio will join Mike Trout (2012) and Vada Pinson (1959) as the only players 20 years old or younger to reach the 20-20 mark.

It’s one thing to simply be a 20-year-old in the Majors -- Chourio is the first player this young to play 125-plus games in a season since Juan Soto in 2019 and the first Brewer since Robin Yount in 1976. It’s another thing to perform like one of baseball’s best players. So let’s take a look at how Chourio turned his rookie year from disappointing to historic.

A dramatic reversal

It wasn’t all sunshine and rainbows for Chourio as he began his MLB career.

In his first 50 games through the end of May, Chourio was hitting .210/.254/.327 with five home runs while striking out in 27 percent of his plate appearances. Chourio’s .587 OPS was tied for the 19th-worst mark among hitters with at least 150 plate appearances. While it was certainly impressive that Chourio was even in the Majors at his age, it was perhaps fair to wonder if it’d take him some time to fully blossom.

So much for that. Since June 1, Chourio is hitting .317/.377/.549 with 14 home runs and 13 stolen bases. His .926 OPS is 11th-best among qualified hitters in that time, putting him right around hitters such as Freddie Freeman, Rafael Devers and fellow NL Rookie of the Year candidate Jackson Merrill. Chourio has racked up 3.5 fWAR during that span, tied for the 12th-best mark in the Majors.

Chourio’s improvements are even more impressive when you consider the clear changes he’s made regarding the quality and quantity of his contact.

Chourio through May 31 vs. since June 1

Hard-hit rate: 41.9% vs. 47.6%
Average exit velocity: 87.0 mph vs. 90.3 mph
Chase rate: 36.4% vs. 30.3%
Whiff rate: 30.1% vs. 23.9%
Expected wOBA: .277 vs. .374

Being able to simultaneously make significantly more contact and better contact is a staggering achievement, especially for a player so young and with so little experience. And it all started with a refined approach to the plate.

“What’s kept him in the big leagues is his better understanding of the zone,” manager Pat Murphy recently told MLB.com’s Brewers beat writer Adam McCalvy. “He’s just developing, but his talent level was good enough to keep him in the big leagues in this particular year on this particular team.”

The new Chourio

Through the end of May, Chourio nearly had five times as many strikeouts (47) as walks (10). Since the calendar flipped to June, Chourio has only struck out 52 times compared to his 25 walks. Since Chourio has only struck out in 16.6 percent of his plate appearances since June compared to the 27.0 percent mark he had through the end of May, it’s allowed him the opportunity to do more damage on balls in play.

Chourio’s barrel rate and average launch angle largely remained the same in both spans but you can see the difference in his hard-hit rate (batted balls with 95-plus mph exit velocities) and average exit velocity (up 3.3 mph). Listed at six feet and 198 pounds, Chourio has much more power than you might expect.

That pop was on full display on August 27 when Chourio crushed a 449-foot home run off the scoreboard at Milwaukee’s American Family Field. It was the longest home run hit in Chourio’s young career and the farthest by a Brewers hitter this season. Since Statcast began tracking in 2015, the only other players to hit a homer that far before their 21st birthdays are Carlos Correa, Fernando Tatis Jr., Ronald Acuña Jr. and Vladimir Guerrero Jr.

Chourio’s progression into a star and improvements since June were perhaps best encapsulated during his Labor Day performance. Chourio took walks in each of his first three plate appearances, setting a career high and marking the fourth time he recorded multiple walks in a game.

In his next plate appearance, Chourio blasted a grand slam, his second of the season. He became the first player age 20 or younger to draw three walks and hit a grand slam in a game since Andruw Jones in 1997.

A star is born?

Could this version of Chourio -- the one we have seen since June -- be his new baseline? It’s not inconceivable, given Chourio’s previous prospect status and the fact that he is producing like this in a prolonged stretch in his rookie year at age 20.

If you extrapolate Chourio’s production in 77 games since June across a full 162-game season, the youngster would be on pace for 29 home runs, 27 stolen bases and 7.4 WAR. That type of season would immediately vault Chourio into the conversation for best players in baseball.

To put that type of season into perspective, only 12 players have reached the 30-30 mark and 7-plus WAR in a single season in the 21st century: Ronald Acuña Jr. (2023), Mookie Betts (2018), José Ramírez (2018), Mike Trout (2012), Ian Kinsler (2011), Matt Kemp (2011), Ryan Braun (2011), Jacoby Ellsbury (2011), David Wright (2007), Hanley Ramirez (2008), Grady Sizemore (2008) and Vladimir Guerrero (2002). They’ll likely be joined by Shohei Ohtani and Bobby Witt Jr. this season.

But even factoring in his sluggish start, Chourio’s first big league season puts him on a path toward greatness. He stands a good chance of finishing with at least 20 homers, a 110 OPS+ and 3 WAR, and only six other rookies in MLB history have hit each of those thresholds in a season at age 20 or younger. Four are in the Hall of Fame (Ted Williams, Willie Mays, Frank Robinson and Orlando Cepeda), and two seem like locks to get there one day (Mike Trout and Bryce Harper).

While it took Chourio a little while to get going, we’re seeing why he was a highly-touted prospect for so long and why the Brewers rewarded him with his extension before the season. Now, Chourio is the most exciting player on a Brewers team that looks poised to make noise in the playoffs this season.