Amid a 2021 Major League Baseball season marked by historic offensive futility, there's actually some intriguing overlap between the league's best hitters and its youngest hitters.
To wit, consider the splits for hitters 24 and younger and those 25 and older:
In defense of the 25-and-older crowd, that 97 wRC+ isn't a historically embarrassing figure. It's only three ticks below the average mark of 100 and a far sight better than the 92 wRC+ that 25-and-older hitters had back in 1935.
But that 102 wRC+ that the 24-and-younger crowd is working on? That's the highest such mark in 121 years of MLB's modern era.
Of the many explanations for this historic occasion, there's no better place to start than with the 20-somethings who rank first, fifth and 12th among all hitters in wRC+: Vladimir Guerrero Jr. (198), Fernando Tatis Jr. (189) and Ronald Acuna Jr. (163).
The New and Improved Vladimir Guerrero Jr.
Where the 23-year-old Acuna and 22-year-old Tatis are concerned, it's certainly fair not to be surprised at their stellar performances. Acuna was the National League Rookie of the Year in 2018, and he and Tatis have three Silver Sluggers and two top-five MVP finishes between them.
The 22-year-old Guerrero, however, is a different story.
As the son of a revered Hall of Famer and the game's No. 1 prospect at the time, Guerrero was saddled with great expectations when he debuted for the Toronto Blue Jays in April 2019. But between '19 and 2020, his first 183 major league games yielded an unspectacular .269/.336/.442 line and 24 home runs.
On the plus side, there were crucial things Guerrero did well. Per his 84th percentile strikeout rate in 2020, one of them was put the ball in play. By way of his 93rd percentile exit velocity, making loud contact was another.
There was therefore only a short leap between Guerrero and superstardom, and it wasn't hard to pinpoint how he could take it. For one, he needed to get in better shape. For two, he needed to sharpen his strike-zone discipline. Lastly, he needed to get more of his hard-hit balls in the air.
Well, he's now hitting .333/.443/.661 with 15 home runs precisely because there are check marks in all three of those boxes.
It is to Guerrero's credit that he followed through on his dedication to get in better shape this offseason. He's also reduced his rate of swings outside the zone, allowing him to become the league's fifth-biggest gainer in walk percentage.
With an average of 94.8 mph, Guerrero trails only Aaron Judge and Evan Longoria in
exit velocity. He's also hitting line drives and fly balls on a career-best 46.0 percent of his batted balls, so the 117 mph, 461-foot shot he hit Monday was perhaps inevitable:
The other remarkable thing about Guerrero's dominance is just how consistently it's been on display. His OPS has been over 1.000 after 41 of his 46 games. In the other five, it's still been over .900.
Never mind a potential All-Star nod and Silver Slugger Award. At this rate, Guerrero could become the player to beat for the American League MVP Award.
The Familiar Yet Still Improved Ronald Acuna Jr. and Fernando Tatis Jr.
Even if they aren't quite on Guerrero's level, both Acuna (98th percentile) and Tatis (95th) are also standouts on the exit velocity leaderboard.
Where they clearly have Guerrero beat is that they can run. Acuna and Tatis have 16 combined stolen bases, which points to how the Atlanta right fielder and the San Diego Padres shortstop have sprint speeds in the 96th and 95th percentiles.
But while it isn't exactly news that Acuna and Tatis boast elite power and speed, they have added new wrinkles.
For Acuna's part, his .276/.380/.622 line and 15 home runs have much to do with the progress he's made with his own zone discipline. He's swinging at only 16.5 percent of the pitches he's seeing outside the strike zone, which has helped pave the way to a career-high 0.7 walk-to-strikeout ratio.
Yet he's done so while also dramatically improving his coverage outside the zone, where his .267 average and .600 slugging percentage are career bests. You know, just in case you were wondering if that grand slam he hit Friday was an anomaly:
Contrary to Guerrero and Acuna, Tatis is actually taking hacks outside the zone at a higher rate than he did in 2020. Because he's often coming up empty on those swings, there's an easy explanation for why his swing-and-miss rate is all the way down in the 19th percentile.
But in fairness to Tatis, separate stints on the injured list for a left shoulder injury and positive COVID-19 test haven't made it easy for him to get into a rhythm in the 30 games he's played. To boot, the former event even necessitated a change in his swing mechanics. Whereas he used to do so with one hand, he now follows through with both hands.
Judging by his .307/.380/.711 line and 13 homers, that adjustment hasn't cost him where it counts. His new follow through also seems to have boosted his already impressive all-fields power. He's slugging 1.068 on balls up the middle and to the opposite field, compared to .860 across 2019 and 2020.
Which brings us to yet another grand slam:
If the season were to end today, Acuna would probably win the NL MVP Award even despite Atlanta's 23-24 record. But if Tatis can stay healthy and help keep the Padres atop the NL West, he may well have the best claim at the end of the season.
This Youth Movement Isn't Just 3 Players
Though Guerrero, Acuna and Tatis are the headliners, they also represent not even half of the 24-and-under hitters who've done better than a 140 wRC+ over at least 100 plate appearances:
- 3B Austin Riley, ATL: 159 wRC+, 9 HR
- 3B Rafael Devers, BOS: 150 wRC+, 13 HR
- CF Trent Grisham, SDP: 149 wRC+, 6 HR
- DH Yordan Alvarez, HOU: 148 wRC+, 7 HR
It's also a near certainty that Juan Soto, 22, will throw his hat into the ring as well. A stint on the IL with a strained left shoulder has contributed to a slow start, but he previously achieved historic greatness with a 152 wRC+ across his age-19, -20 and -21 seasons from 2018 to 2020.
Also worth shouting out are Miami Marlins second baseman Jazz Chisholm Jr. (127 wRC+), St. Louis Cardinals right fielder Dylan Carlson (121) and Blue Jays shortstop Bo Bichette (115). And while they haven't quite clicked yet, it should surprise nobody if New York Yankees shortstop Gleyber Torres (110) and Astros right fielder Kyle Tucker (110) rediscover the star-caliber form they've previously shown.
Regarding how, exactly, the youngest hitters in MLB are succeeding at a historic level while everyone else is having such a hard time, it's not necessarily because they're better pure hitters. Indeed, the 24-and-younger crowd lags behind the 25-and-older crowd in both walk rate (8.6 to 9.0) and strikeout rate (25.3 to 24.0).
But as you'd perhaps expect, the youngsters have a distinct edge in the more athletic aspects of the game. They best their elders in average exit velocity (89.3 to 88.9 mph) and baserunning value (9.1 to minus-9.1).
As long as those advantages hold and Guerrero, Acuna and Tatis keep doing their thing, MLB's youth movement should maintain forward momentum throughout the season.