There have been 20 teenagers to start on Opening Day in the Modern Era (since 1900), according to the Elias Sports Bureau. All of them have been position players -- the youngest pitcher on record to start on Opening Day was Catfish Hunter at 20 years, 4 days old in 1966.
The Padres' Fernando Tatis Jr. was 20 years, 85 days old on Opening Day 2019, just out of his teens. No player that young had started on Opening Day since Adrian Beltre in 1999 -- and he retired this offseason. In other words, it’s been a while.
Tatis is the eighth-youngest position player to start on Opening Day in the last 50 seasons -- six individuals did so, including Robin Yount twice. Overall, 31 different position players have started Opening Day at Tatis' age or younger in the Modern Era, according to the Elias Sports Bureau.
Here is a look at the 20 teens who have started on Opening Day (starting with the youngest), including one who pulled off the feat twice.
Granny Hamner, SS: 17 years, 356 days in 1945 (Phillies)
Hamner debuted in September 1944, in part because many players were fighting in World War II and there were roster spots available. He played in his first Opening Day in 1945, going 0-for-4 in a Phillies loss to the Dodgers. That was one of 14 games he’d play in 1945. He didn’t play in more than 25 games in any season until 1948. The following year, he received MVP votes for the first of what would be six times.
Gene Mauch, SS: 18 years, 152 days in 1944 (Dodgers)
Mauch made his Major League debut on Opening Day in 1944 for the Dodgers, who were in need of players during wartime. He went 0-for-2 in a Dodgers loss to the Phillies. Mauch played in five games that season and did not return to the Majors until 1947 as a 21-year-old. Just as he began his playing career at a young age, Mauch became the Phillies manager in 1960 at the age of 34.
Ed Kranepool, RF: 18 years, 152 days in 1963 (Mets)
Kranepool made his debut in September 1962 for the Mets, then started his first Opening Day the following season. Batting third in the opener, he went 0-for-4 in a Mets loss to the Cardinals. Kranepool would play his entire 18-year career for the Mets, winning the 1969 World Series with the club and representing the team in the 1965 All-Star Game.
Robin Yount, SS: 18 years, 201 days in 1974; 19 years, 204 days in 1975 (Brewers)
Yount’s Major League debut came on Opening Day in 1974 as an 18-year-old. He hit ninth in a Brewers loss to the Red Sox. Yount hit his first home run on April 13 that year, and went on to hit three more as an 18-year-old. He’s still the last player to hit a home run in the Majors before turning 19. Still a teenager on Opening Day 1975, Yount became the only teenager to homer on Opening Day, in a Brewers loss, also to the Red Sox.
Stuffy McInnis, SS: 18 years, 205 days in 1909 (Athletics)
McInnis went 1-for-4 in his Major League debut on Opening Day in 1905, as his Philadelphia Athletics beat the Boston Red Sox. McInnis would go on to be a four-time World Series champion, winning two with the Athletics (1911 and 1913) and one each with the Red Sox (1918) and Pirates (1925).
Rusty Staub, RF: 19 years, 8 days in 1963 (Colt .45s)
Staub hit cleanup as a 19-year-old on Opening Day in 1963, going 1-for-3 in a Houston loss to San Francisco. He debuted just days after his 19th birthday. Staub started his career at a young age, and ended it after more than 2,900 games as a 41-year-old. He was 41 years, 188 days old in his final game, on Oct. 6, 1985, with the Mets.
Bobby Doerr, 2B: 19 years, 13 days in 1937 (Red Sox)
A teenage Doerr hit leadoff for the Red Sox on Opening Day, going 3-for-5 in a game Boston won, 11-5, over the Athletics. Doerr played in just 55 games in 1937, but played in 100 or more in every season from 1938-51 except 1945, when he served in the military. Doerr was a nine-time All-Star for the Red Sox and is in the National Baseball Hall of Fame.
Cass Michaels, SS: 19 years, 44 days in 1945 (White Sox)
Michaels debuted in the Majors for the White Sox at age 17 in 1943 and played in games both as a 17-year-old and an 18-year-old. But he didn’t play in an opener until 1945, when he was 19. He went 0-for-3 in a White Sox win over the Indians.
Tony Conigliaro, CF: 19 years, 100 days in 1964 (Red Sox)
A teenage Conigliaro made his Major League debut for the Red Sox on Opening Day in 1964. He went 1-for-5 in a Red Sox win over the Yankees. Conigliaro went on to hit 24 home runs that season, which is still the mark for a teenager in a single season. (Bryce Harper hit 22 in 2012, as did Juan Soto in 2018.)
Al Kaline, RF: 19 years, 115 days in 1954 (Tigers)
The Hall of Famer had debuted at age 18 in 1953, but started in his first Opening Day in 1954. The Tigers defeated a young Don Larsen and the Orioles, 3-0. Kaline went on to be an 18-time All-Star, 10-time Gold Glove winner and won a batting title, as well as a World Series. He was 39 years, 287 days old in his final game. on Oct. 2, 1974.
Ken Griffey Jr., CF: 19 years, 133 days in 1989 (Mariners)
Griffey's first Opening Day start was also his Major League debut. The Hall of Famer went 1-for-3 with a double batting second in a Mariners loss to the A’s. He finished third in AL Rookie of the Year voting with a .264/.329/.420 season and 16 home runs. He'd go on to make 13 All-Star teams and win an MVP Award, 10 Gold Gloves and seven Silver Sluggers. He was 40 years, 191 days old in his final game, on May 31, 2010.
Hank Ruszkowski, C: 19 years, 158 days in 1945 (Indians)
In the same game Cass Michaels started as a teenager, Ruszkowski went 2-for-3 in an Indians loss. He’d debuted in September 1944 as an 18-year-old, playing in three games at the end of the season. He appeared in just 40 games in his career, hitting three home runs, all in 1947.
Mickey Mantle, RF: 19 years, 179 days in 1951 (Yankees)
Batting third in his first Opening Day and his Major League debut, the Hall of Famer went 1-for-4 in a Yankees win against the Red Sox. Mantle would go on to hit 13 home runs as a teenager for the Yankees, before hitting 23 the following season as a 20-year-old. He didn't have another season with fewer than 15 home runs for the rest of his career.
Billy Consolo, 2B: 19 years, 238 days in 1954 (Red Sox)
Consolo hit leadoff for the Red Sox, notching a third-inning single off Bobby Shantz in a Red Sox loss to the Athletics. Consolo had debuted as an 18-year-old in April 1953, but after Opening Day.
Bob Kennedy, 3B: 19 years, 242 days in 1940 (White Sox)
Kennedy hit leadoff for the White Sox and went 0-for-4 in a 1-0 loss to Bob Feller and the Indians. He had debuted and played three games in late 1939, then played the full 154-game schedule in 1940 for Chicago.
Vada Pinson, RF: 19 years, 247 days in 1958 (Reds)
Pinson hit second ahead of Frank Robinson in an Opening Day loss to the Phillies, which doubled as his MLB debut. He was on four All-Star teams and finished as high as third in MVP voting -- in 1961.
Sibby Sisti, 2B: 19 years, 265 days in 1940 (Bees)
Sisti hit leadoff and went 2-for-4 with a double for the Boston Bees (the Braves franchise) in a loss to the Dodgers. Sisti had debuted as an 18-year-old in July 1939.
Brooks Robinson, 3B: 19 years, 332 days in 1957 (Orioles)
The Hall of Famer debuted in September 1955 as an 18-year-old, but started his first Opening Day in 1957 before turning 20 in May. The Orioles beat the Washington Senators, 7-6. Robinson was an All-Star each season from 1960 through 1974 and won 16 Gold Gloves, the most of any position player. He was 40 years, 87 days old in his final game, on Aug. 13, 1977.
Rogers Hornsby, SS: 19 years, 351 days in 1916 (Cardinals)
Hornsby had debuted in September 1915, but played in his first Opening Day in 1916. He went 2-for-3 in a Cardinals win over the Pirates. In that 1916 season, Hornsby hit .313 with 15 triples. He went on to win seven batting titles and won the Triple Crown twice. He was 41 years, 84 days old in his final game, on July 20, 1937.
Adrian Beltre, 3B: 19 years, 363 days in 1999 (Dodgers)
Just days before his 20th birthday, Beltre started his first Opening Day, a Dodgers win over the D-backs. He had debuted in June 1998, a few months after turning 19. The future Hall of Famer is the last teenager to appear in an Opening Day game, regardless of whether he started or not. Beltre played until he was 39, receiving MVP votes and winning a Gold Glove as a 37-year-old in 2016.
Sarah Langs is a reporter/editor for MLB.com based in New York. Follow her on Twitter @SlangsOnSports.