The Kids Are Alright: This Year’s Rookie Class Has Been Historically Great

Last season’s rookie class introduced us to some instant stars. Julio Rodríguez and Adley Rutschman became the first pair of rookies to reach 5.0 WAR in the same season since Albert Pujols and Ichiro Suzuki in 2001. Teammates Michael Harris II and Spencer Strider were just shy of 5.0 WAR themselves, with the latter’s 4.9 the highest total by a rookie pitcher since Hideo Nomo in 1995. Rodriguez, Rutschman, and Harris were all top-25 position players in baseball by WAR, with Steven Kwan not far behind at 30th, and Strider finished eighth among pitchers despite spending the first two months of the season in the bullpen.

This year, an arguably more impressive barrage of talented youngsters has arrived in clubhouses across the league. Corbin Carroll currently ranks eighth in WAR thanks to a .376 wOBA and the most baserunning value in the league at 11.0 runs above average; he’s running away with the NL Rookie of the Year Award. James Outman is helping the Dodgers out with a productive (if streaky) bat and centerfield defense worthy of his name. Gunnar Henderson shook off a slow start at the plate with a productive summer, clearing 3.0 WAR before the calendar turned to September and positioning himself as an award candidate in the AL. Matt McLain (who is battling an oblique injury at the moment) and the Giants’ Patrick Bailey didn’t even arrive until mid-May, but both have reached the 3.0 WAR mark in under 100 games.

As bright as those at the top have shone, what might make this year’s class stronger than last year’s is its remarkable depth, particularly among position players. Josh Jung made the AL All-Star team before being sidelined with a thumb fracture in August. Francisco Alvarez has complemented strong defense behind the plate with good power for a catcher. Edouard Julien looks like a legitimate bat in a Minnesota infield in need of production after dealing Luis Arraez. Tons more have put up some impressive value in limited action; José Caballero, Zack Gelof and Royce Lewis, for example, are playing at a pace of 4.0 WAR per 500 PA. All told, 12 rookie position players have reached 2.0 WAR already; just nine reached that mark by the end of the season in 2022. And that list doesn’t include players like Elly De La Cruz, Yainer Diaz, Freddy Fermin, Spencer Steer, or Triston Casas.

The pitching class is thinner, but there’s still a contingent of rookies turning heads. Kodai Senga had pro experience in Japan, but his MLB debut has been impressive: a 3.17 ERA, 3.52 FIP, and 3.76 xFIP in 24 starts. Tanner Bibee has been good enough in Cleveland to warrant ROY votes, and his teammates Logan Allen and Gavin Williams have been strong complements. Andrew Abbott has been the best of a dozen or so rookie Reds pitchers, joining McLain, De La Cruz, Steer, Brandon Williamson, and more in the league’s most prolific team rookie cohort. Eury Pérez has been fantastic for the Marlins in 16 starts (interrupted by a month of workload management in the minors). Then there’s Cole Ragans, who’s been the talk of the league after joining the Royals’ rotation and leading all MLB starters with a 1.72 ERA, 1.46 FIP, 2.19 xFIP, and 1.8 WAR in August. In bullpens across the league, Yennier Cano (another 2023 All-Star), Gregory Santos, and Justin Topa have joined the ranks of this season’s dominant relievers.

But how does the overall class measure up? As a group, 2023 rookies have amassed 110.5 WAR as of Tuesday morning, surpassing last year’s already impressive full-season total of 101.6 in over 4,500 fewer plate appearances and 1,500 fewer innings pitched. The last class to reach higher heights was the class of 2015, which might have a case for the best in recent history with Kris Bryant, Francisco Lindor, Carlos Correa, Joc Pederson, Kyle Schwarber, and Noah Syndergaard. This year’s class is unlikely to catch them at 126.8 WAR, but the 2023 rookies already rank fourth among rookie classes of the last 100 years, the most productive of which have come in the 21st century.

Some of this is a matter of usage; we are in an era where more plate appearances and innings are going to rookies, generally speaking. But it’s also only Labor Day — this class has nearly a month left to play. That they’ve already surpassed last year’s, and nearly every other year’s, in production is pretty remarkable.

They owe most of this to the position players. On a rate basis, 2023 rookie hitters have put up 1.26 WAR per 500 PA — not quite matching the class of 2015’s 1.30, but far ahead of the next-best class of the last century, the class of 1987, at 1.04. They’re hitting at a clip of 92 wRC+, which would be the best mark for a rookie class in modern baseball history, and their 63.4 WAR ranks second only to that 2015 class in the last hundred years. Comparing statistics like WAR and wRC+ values from seasons before those stats were developed can feel a little funny, but it’s clear that this cohort of position players stands up against its historical counterparts.

The pitchers are no slouches, either; while they don’t measure up quite as strongly historically, their 1.15 WAR per 200 innings are the most since 2016, when rookie arms produced 1.35 WAR for every 200 innings they threw.

Successful rookie classes are a sign of sophisticated player development systems, and it’s clear that franchises around the league have been increasingly effective in preparing their minor leaguers for the big leagues. The fact that the classes of the last two seasons have been so position player-heavy may hint that the barriers to entry for them could be less inhibitive than those that pitchers face in today’s game. Rookie position players, after all, have a handful of ways to contribute. Masataka Yoshida has performed at the plate despite struggling with the glove; Ezequiel Tovar’s stellar shortstop defense in Colorado has yielded him 1.6 WAR despite an anemic bat; Esteury Ruiz has found a way to stick around in Oakland with mostly just value on the basepaths. For pitchers, there’s more than one way to get an out, but if you can’t get outs, you’re in trouble.

When it comes to award season, this year’s class may not appear as flashy as last year’s; after Carroll, the 2023 group is giving less “instant stars” and more “solid big leaguers with a chance of becoming stars.” But the depth is serious. Nearly every team has seen some significant contribution from first-year players, and while surely some of these early-career successes will fade, some will plant themselves firmly among baseball’s next generation, making themselves key puzzle pieces on future championship teams.

Unfortunately, with Carroll’s Diamondbacks, McLain’s Reds, Jung’s Rangers, and Bailey’s Giants slipping in recent weeks, this rookie class may not have the chance to impact this season’s championship outcome quite as much as it seemed they might have back in early August. But Outman, Henderson, Julien, and more are still more than likely to be showcased in October, and if their peers can inject some much-needed September energy to their clubhouses, they could have a shot of bringing their already thrilling professional journeys to baseball’s biggest stage. In any case, we should be looking forward to seeing a lot more of these faces for years to come.