The impact of Corey Seager and the revolution he's leading across baseball

There has been a rise in impactful young hitters, slugging shortstops and tall shortstops, and Seager, the Dodgers' sensation who just won the National League Rookie of the Year Award unanimously, is a factor in each category.

Corey Seager is 22 years old, played only 390 minor league games before becoming an instant major league star for the Dodgers as a call-up last year and is now the unanimous winner of the 2016 National League Rookie of the Year Award, as well as a finalist for NL MVP honors. He is also just the latest in a recent line of players to make a huge impact at an extremely young age. The Marlins' Giancarlo Stanton won the NL slugging title at 22 in 2012; the Orioles' Manny Machado had his first of two top-10 AL MVP finishes in '13 at age 21; the Angels' Mike Trout won the AL MVP at 22 in '14; the Nationals' Bryce Harper became the youngest unanimous MVP at age 22 in '15; the Cubs' Kris Bryant won the NL Rookie of the Year last season at age 23 and is the likely NL MVP this year; and the Red Sox' Mookie Betts is an AL MVP finalist this year at 23.

The lode of young talent at shortstop is particularly rich. Until this season, there had never been a year in baseball history in which more than two shortstops age 23 or under hit 15 home runs. This year Seager (who hit 26) was one of six shortstops to do so, joining the Rockies' Trevor Story (27), the Red Sox' Xander Bogaerts (21), the Cubs' Addison Russell (21), the Astros' Carlos Correa (20) and the Indians' Francisco Lindor (15). Lindor and Russell, both 22, became the youngest pair of starting shortstops in World Series history. We are looking at the greatest class of young shortstops ever known.

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Seager is the best of the bunch. I would take his next 10 years over all others, though it’s close. If you like the defense of Lindor or the power potential of Correa, you can construct a convincing argument for them.

Seager is listed at 6'4" and 215 pounds, though in person he appears even bigger. His size has led to speculation that he will have to move off shortstop to a corner position. I don’t buy it, because that assumption is made purely on the basis of his size. When you actually watch Seager defend—particularly on balls when he has to range low and to his backhand, where footwork and body control are vital—you have to conclude that he is a natural shortstop. Said one rival manager, “Every time he makes that play I feel like I should be surprised because of his size, but we shouldn’t be surprised any more. He’s a very, very good defender.”

So what is going on here? Seager seems to be a proxy for something much larger happening in the game. Is baseball relying more on younger players? Why are we seeing so many extremely young players making a major impact? Why has the shortstop position become a power-hitting position? What has happened to the older impact player? I wondered myself, and here is what I found.

PointAfter | Graphiq

1. Major league teams are relying on young hitters more than they have in a generation.

Players who are 25 or younger took 25.9% of all plate appearances this season. That’s the third highest rate in the past 23 years, trailing only 2015 (27.5) and '08 (26.7).

You can credit the reliance on youth in part to the crackdown on steroids and amphetamines. Back in 2004, the first year of testing with penalties for steroids, 25-and-under players took only 16.9% of plate appearances. Steroids could artificially extend the prime years of older players, depressing opportunities for young players. This year, 25-and-under players were given 15,890 more plate appearances than they were a dozen years ago.

It’s not just about the chemicals, though. Young players are benefiting from the growing opportunities in big-time amateur baseball, from travel ball to college, which includes year-round play, advanced instruction and high-pressure, highly competitive environments.

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2. Despite the surge in recent years, the reliance on young hitters is not close to historically high levels.

Before steroids became popular, baseball skewed even younger than what we see today. The percentage of plate appearances for 25-and-under hitters this year (25.9) still is below what it was in 1993 (26.4), as well as the highwater marks of the 1980s (27.2), 1970s (34.0) and 1960s (38.0). Of course, it doesn’t come close to the dark days of athletic training back in the Dead Ball Era (42.6).

Generally speaking, as training and medicine have advanced, so has the ability to retain skills into a player’s 30s—just artificially so through the Steroid Era.

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3. There are fewer young impact hitters today than throughout most of baseball history.

This surprised me. First, let’s define a young impact hitter as any qualified hitter age 23 or younger who posts an OPS+ of 120 or better. This year we saw four such prodigies: Seager (137 OPS+), Betts (131), Machado (128) and Correa (123). Now let’s look at different eras in history and, because of expansion, consider not just the raw number of such hitters but also the number of team seasons (TS) per young impact hitter (YIH).

Years	YIH	TS	TS/YIH
2004–16	39	390	10.0
1993–2003	22	320	14.5
1977–92	52	390	7.5
1961–76	73	350	4.8
1939–60	56	352	6.3

The 1960s and '70s were the golden age for young hitters, when hitting prodigies came along about twice as often as they do today. What we’re seeing now is what only looks like a golden age of young hitters because of what we saw in the Steroid Era, but nothing close to it when viewed with a wider lens.

4. The best players in baseball are young.

On Thursday—barring an upset win by the Nationals' Daniel Murphy, who is 31—the MVPs will be Bryant, 24, and either Betts, 23; Trout, 24; or Houston's Jose Altuve, 26. That will make it 18 straight MVPs who are 30 or younger. The last MVP older than 30 was Alex Rodriguez, who was 31 in 2007 and is an admitted steroid user. Here’s a quick thumbnail look at how the MVP landscape has changed, assuming a win by Bryant.

Timeframe	Age 26 or Younger	Age 31 or older
2008–16	9	0
1999–2007	3	6

This is just another reminder that the game is chock full of young hitting stars. Seager looks like he will be a regular contender for MVP awards. Who’s got next? They may not be in Seager’s class, but among the youngest and most advanced of the coming wave of potential impact players are the Red Sox' Yoan Moncada and Andrew Benitendi, both 21; the Phillies' J.P. Crawford, also 21; and the Mets' Amed Rosario, 20.

5. The power at shortstop is not a fluke.

At his size, Seager is not the anomaly Cal Ripken was. As the general population grows taller and heavier, so, too, is a position that we traditionally associated with small, light-hitting, glove-centric players.

Until 2015, there had never been a baseball season with more than three qualified shortstops that stood 6'3" or taller. Then in '15, we saw four such giants at shortstop; in '16, we saw five. There were as many 6'3" qualified shortstops this year as in all seasons combined between 1901 and '76. It’s time to drop the scouting bias against tall shortstops.