We saw a bunch of MLB breakthroughs this season, and today, we will learn which players will join such immortals as Todd Hollandsworth and Andrew Bailey as Rookies of the Year in their respective leagues. The ballots submitted by BBWAA voters goes three names deep, and that is how long my ballot goes as well.
American League
1. Shohei Ohtani–Los Angeles Angels: If newsworthiness were a criteria for Rookie of the Year voting, Shohei Ohtani would win this in a landslide (and portly Minnesota Twins zero-true-outcomes superstar rookie Willians Astudillo would finish second, or at least appear on my ballot). The two-way sensation, a man who can reach triple-digit miles per hour as a starting pitcher and belt an endless array of dingers as a designated hitter (and reportedly is a good defensive right fielder, though we didn’t get to see this play out), proved worthy of the hype in 2018. While Ohtani was hampered by injuries, including an arm injury which necessitated Tommy John surgery which will keep Ohtani from pitching in 2019 (though he should still be able to hit), his numbers when he did play met even realistically high expectations. Among the 247 hitters with at least 350 plate appearances in 2018, Shohei Ohtani ranked eighth with a 152 wRC+. In his ten starts as a pitcher, Ohtani was 20% above-average by ERA and 15% above-average by FIP. By combined batting and pitching FanGraphs Wins Above Replacement, he was the AL’s best rookie, and he deserves some bonus points for effectively saving the Angels a roster spot.
2. Joey Wendle–Tampa Bay Rays: A far less glamorous pick than the much-hyped Shohei Ohtani, the 28 year-old second baseman whom the Rays acquired the previous off-season for something called Jonah Heim, broke out for a Tampa Bay team that would’ve gotten more attention had they not played in a division with a loaded top two teams. In 545 plate appearances, Wendle triple-slashed .300/.354/.435 while playing above-average defense at a premium position and stealing 16 bases while only being caught four times.
3. Brad Keller–Kansas City Royals: In a mostly forgettable season in Kansas City, the emergence of Brad Keller was one of the few bright spots for the Royals. In 140 1/3 innings split between starting and relieving, Keller was very good by ERA, registering a 3.08 mark, and while his somewhat pedestrian strikeout rate limited his FIP upside, a 3.55 FIP is certainly workable. Keller gets a slight nod over Miguel Andujar, but the New York Yankees third baseman’s defense was too, frankly, abhorrent to ignore.
National League
1. Ronald Acuna Jr.–Atlanta Braves: After spending most of the season as one of many NL Rookie of the Year candidates, the much-hyped Acuna (he is the only prospect whose hype entering 2018 could rival that of Shohei Ohtani) cemented his victory in August, when he managed a 190 wRC+ and 11 home runs in 131 plate appearances. This was more a case of Acuna winning the award that the also-rans losing it–twenty year-olds simply aren’t supposed to triple-slash .293/.366/.552 in 487 plate appearances.
2. Juan Soto–Washington Nationals: A top, if not quite Acuna-level, prospect, Juan Soto arguably had the more impressive offensive season of the pair. Although slightly less powerful of a hitter, Soto won rave reviews for his uncanny plate discipline, particularly rare for a 19 year-old, walking in 16% of his plate appearances on the season and posting a 145 wRC+ on the season with a perfectly reasonable .338 batting average on balls in play. He was a worse fielder and base runner than Acuna (though not by an enormous amount, on either end), so he finishes second, though there are many years where Juan Soto would run away with the Rookie of the Year award.
3. Harrison Bader–St. Louis Cardinals: There are countless strong candidates for the ballot–rookie pitchers Walker Buehler (the third finalist) and Jack Flaherty and outfielder Brian Anderson are among the notables–but Wins Above Replacement of both the FanGraphs and Baseball Reference variety agree that the three best rookies in the NL this season were Acuna, Soto, and the rookie Cardinals center fielder Harrison Bader. Far less ballyhooed as a prospect and far more reliant on super defensive metrics than the two ahead of him, Bader is easily a higher risk to come back down to Earth in future seasons, but in the meantime, he did have the 2018 he had, in which he was an above-average hitter and arguably the best defensive outfielder in baseball.