Youth is the name of the game in baseball these days, and Vladimir Guerrero Jr. and Fernando Tatis Jr. just proved that the future is very much now.

Guerrero belted his 48th home run of 2021 in Toronto's regular-season finale Sunday to clinch a share of the American League homer title with Royals catcher Salvador Perez. Over in the NL, Tatis finished with 42 dingers of his own to take home the NL crown.

As sons of famous big league sluggers, the concurrent rise of Guerrero and Tatis is exciting enough. But now they are both league home run champions -- and each of them achieved that distinction at just 22 years of age. Why is 22 significant? Only eight previous 22-or-younger players had ever finished a season atop an AL or NL home run leaderboard.

Guerrero and Tatis are not the youngest league homer champs in AL/NL history -- but they're pretty close. Below is a look at where they rank, per the Elias Sports Bureau, starting from the youngest player to ever do it.

Tony Conigliaro, 1965 Red Sox (20 years, 269 days)
32 HRs (led AL)

Conigliaro is atop numerous "youngest" lists, including this one. He got off to one of the greatest starts to a career in history, by certain metrics, before an August 1967 hit by pitch in the face changed the course of his career. Only one player in baseball history hit more career homers before turning 22: Mel Ott, with 86. Conigliaro hit 84, including his 32 in ‘65 as a 20-year-old. Willie Mays led the NL and the Majors that year, with 52 home runs.

Sam Crawford, 1901 Reds (21 years, 171 days)
16 HRs (led MLB)
Back in 1901, in the first year of the AL, 16 homers were plenty to lead the Majors. Crawford led the NL, and his 16 were two more than AL leader Nap Lajoie, as well as a career high. But he did lead his league one other time -- in 1908 with the Tigers (seven). A 1916 magazine article about Crawford noted that he was considered the ideal slugger in his day: “While we are no sculptor, we believe that if we were and were looking for a model for a statue of a slugger we would choose Sam Crawford for that role.”

Eddie Mathews, 1953 Braves (21 years, 349 days)
47 HRs (led MLB)
Mathews finished his career with 512 home runs, tied for 23rd-most all-time. How do you join the 500-homer club? Getting a fast start sure helps. Mathews hit 25 homers as a rookie in 1952, receiving Rookie of the Year votes in the NL, with Joe Black of the Dodgers winning the award. Then as a 21-year-old in ‘53, Mathews left no doubt, leading the Majors with 47 homers. He finished second in the NL MVP vote to Roy Campanella. Mathews led the Majors in homers again in 1959 when he hit 46.

Vladimir Guerrero Jr., 2021 Blue Jays (22 years, 201 days)
(48 HRs, tied for MLB lead)
After a decent start to a career that only underwhelmed because of fans' sky-high expectations, Guerrero broke out with a massive 2021 campaign and thrilled fans with titanic homers to every part of the ballpark. His 48 round-trippers surpassed Mathews' record for the most by any AL/NL player in his age-22 season or younger, and he made a legitimate push for the AL MVP Award (though two-way sensation Shohei Ohtani also made history for the Angels).

Fernando Tatis Jr., 2021 Padres (22 years, 274 days)
42 HRs (led NL)
Tatis solidified his standing among the game's best all-around stars, submitting an NL MVP-caliber season with 42 dingers, a .611 slugging percentage and 25 stolen bases. Tatis' homer total was all the more impressive given that he only played in 130 games because of several stints on the injured list. He is the only primary shortstop to knock at least 40 homers in an age-22 or younger season.

Ty Cobb, 1909 Tigers (22 years, 293 days)
9 HRs (led MLB)
By the time Cobb turned 26, he had already led his league, if not the Majors, in batting average six times, and had similar accolades to his name in other categories, too. Those include the 1909 season, when a 22-year-old Cobb led everyone in homers with ... nine. It was a different era, but he led the way -- the only time he ever topped his league in home runs.

Johnny Bench, 1970 Reds (22 years, 298 days)
45 HRs (led MLB)
By the start of the 1970 season, Bench had already won a Rookie of the Year Award, received MVP votes in two separate seasons, won two Gold Gloves and was a two-time All-Star. And he was still just 22 years old. He continued the strong start to his Hall of Fame career by crushing 45 homers and driving in 148 runs in ‘70, leading the league in both categories, before he even turned 23 in December of that year. It was one of two times he’d lead the Majors in homers, also doing so in 1972, when he hit 40.

Joe DiMaggio, 1937 Yankees (22 years, 312 days)
46 HRs (led MLB)

As a 21-year-old rookie in 1936, DiMaggio tied for the Major League lead in triples with 15, along with Earl Averill and Red Rolfe. The following year, he led the Majors in an extra-base hit category again, but this time it was homers. DiMaggio hit .346 and led the Majors in total bases and runs scored in addition to homers, but he finished second in AL MVP voting behind Charlie Gehringer. DiMaggio paced the AL in home runs a second time in 1948, when he hit 39.

Bryce Harper, 2015 Nationals (22 years, 353 days)
42 HRs (tied for NL lead)

Harper’s 2015 season was one for the ages, earning him an NL MVP award. He was the youngest player to win one unanimously. He hit .330 with a .460 on-base percentage and a .649 slugging percentage, with the latter two leading the Majors. His 42 homers were tied with Nolan Arenado for the most in the NL, behind only Chris Davis’ 47. Harper has led the Majors in walks twice since then, but not in homers.

Juan González, 1992 Rangers (22 years, 354 days)
43 HRs (led MLB)

González played in three Major League seasons before 1992, exceeding rookie limits in ‘90. In 1991, he hit 27 homers in 142 games. A year later, he blasted 43 home runs, leading the Majors in a season that ended just before his 23rd birthday. The following season he tied for first in the Majors, hitting an AL-high 46 and tying the Giants’ Barry Bonds. González totaled five 40-home run seasons in his career, but 1992-93 were the only times when he led the AL or the Majors.