Vladimir Guerrero Jr.

Entering 2019 spring training, questions arose as to whether the Blue Jays organization would have Guerrero on the Opening Day roster, or seek to manipulate his MLB service time by assigning him to the minors to begin the season. Keeping Guerrero in the minor leagues for the first two weeks of the season would prevent him from reaching free agency until after the 2025 season. On March 10, the Blue Jays announced that Guerrero had suffered an oblique strain two days earlier and was ruled out for the rest of spring training.

On April 24, 2019, the Blue Jays announced that Guerrero would be called up from Triple-A Buffalo on April 26. Guerrero was considered the top prospect in all of professional baseball prior to being called up, and was hitting .367/.424/.700 with three home runs and eight RBIs during an eight-game stint with Buffalo in 2019. He went hitless in his first three at-bats against the Oakland Athletics before hitting a double in the bottom of the ninth inning and exiting for a pinch runner. Guerrero recorded his first multi hit game, and reached base safely four times, on May 11.

In 2019, he batted .272/.339/.433, with 15 home runs and 69 RBIs in 464 at bats. He hit the ball with the second highest exit velocity (118.9 mph) of all balls hit by major league batters in 2019.

Entering the 2018 season, Guerrero was considered the top prospect in the Blue Jays organization by MLB and Baseball America. On March 23, Blue Jays team president Mark Shapiro announced that Guerrero would begin the season with the Double-A New Hampshire Fisher Cats. Through the first month of the season, he led the Eastern League with a .398 batting average and 30 runs batted in. On June 4, Guerrero was named the Eastern League's Player of the Month after hitting .438 with nine home runs and 28 RBI in May. On June 6, Guerrero was removed from a game against the Akron RubberDucks with a leg injury. Three days later, it was determined that he had a strained patellar ligament in his left knee, and would be on the disabled list for at least four weeks. On July 28, it was announced that Guerrero would be promoted to the Triple-A Buffalo Bisons following his father's induction into the National Baseball Hall of Fame and Museum. Guerrero hit .402 with 14 home runs and 60 RBI in 61 games with New Hampshire. On August 30, the Blue Jays added Guerrero to the roster of the Surprise Saguaros of the Arizona Fall League (AFL).

Guerrero is the son of Vladimir Guerrero, who was elected to the National Baseball Hall of Fame and Museum in January 2018, and the nephew of Wilton Guerrero. He was born in Montreal while his father was playing for the Montreal Expos, and is a Canadian citizen. His cousin, Gabriel, plays for the Blue Jays organization. Guerrero has two daughters.

Guerrero opened the 2017 minor league season with the Class-A Lansing Lugnuts. In a 6–3 win over the Great Lakes Loons on April 7, he hit his first home run of the season. Guerrero was named a Midwest League All-Star on June 7, and on June 29, he was named to the World team roster for the 2017 All-Star Futures Game. On July 6, the Blue Jays announced Guerrero would be promoted to the Advanced-A Dunedin Blue Jays following the All-Star Futures Game. In a game against the Clearwater Threshers on August 31, Guerrero hit a home run to give the Blue Jays a 5–3 victory, with the win ensuring Dunedin would make the Florida State League playoffs. Guerrero finished the 2017 regular season with a .323 batting average, 13 home runs, and 76 RBI in 119 games played. He also walked more than he struck out, with 76 and 62 respectively, and posted a .910 on-base plus slugging percentage (OPS). On September 6, Guerrero was named ESPN's Prospect of the Year. During the offseason, he played in 26 games for the Leones del Escogido of the Dominican Winter League.

Eligible for free agency in 2015, Baseball America ranked Guerrero as the top international free agent, and MLB.com ranked him the fourth-best. He signed with Toronto on July 2, 2015, for $3.9 million. Guerrero was assigned to extended spring training camp to open the 2016 minor league season. Guerrero made his professional baseball debut with the Rookie Advanced Bluefield Blue Jays on June 23. Guerrero hit his first professional home run on June 24, a two-run shot in a 4–2 loss to the Bristol Pirates. On August 12, Guerrero recorded his first multi-home run game, hitting two solo shots in an 18–5 win against the Pulaski Yankees. Later in August, he was named the Appalachian League's All-Star at third base. Guerrero played in 62 games for Bluefield in 2016, and hit .271 with eight home runs, 46 runs batted in (RBI), and 15 stolen bases. On January 24, 2017, MLB named Guerrero the third best prospect at third base heading into the 2017 minor league season.

On May 14, against the San Francisco Giants in Oracle Park, Guerrero hit his first major league home run in the first inning off Nick Vincent. At 20 years and 59 days of age, Guerrero became the youngest Blue Jay to hit a home run, breaking Danny Ainge's record by 18 days. In the sixth inning, with two men on, he hit another home run off Reyes Moronta. He hit two more home runs in the following series against the Chicago White Sox, including one that bounced off the glove of center fielder Leury Garcia and over the wall. Guerrero's four home runs over a six-game road trip earned him the American League Player of the Week Award, and made him the youngest Blue Jay to win the award. On May 22, he hit his first home run at the Rogers Centre off Rick Porcello of the Boston Red Sox. On May 31, Guerrero's sixth home run, against the Colorado Rockies, was the 1,135th home run in May throughout Major League Baseball, breaking the MLB record for most home runs in a single month. On July 8, he broke the single round home run record in the Home Run Derby with a total of 40 home runs after three overtimes in the semifinals against Joc Pederson. He also broke the record for most home runs in a derby with 91, although he lost the final round to Pete Alonso.

Vladimir Guerrero Ramos Jr. (born March 16, 1999) is a Canadian–Dominican professional baseball third baseman for the Toronto Blue Jays of Major League Baseball (MLB). He is the son of former MLB player and Hall of Famer Vladimir Guerrero Sr.. He made his major league debut in April 2019.