It should surprise no one that Ronald Acuña Jr. is about to be named the National League Rookie of the Year for 2018. The numbers he put up and impact he had on the Braves winning the division even beyond the box score are the kinds of measureables that tend to bring hardware with them at season’s end.
So while it’s not a question about Acuña having the best numbers among NL rookies this year, the question is how his numbers stack up to other great players that played a large role in an age-20 season...a group of players that as one may expect is loaded with present and future Hall of Famers.
I left off Doc Gooden because it’s just not easy to compare hitters numbers to pitchers numbers. I also chose to leave off some older Hall of Famers, like Ty Cobb, because comparing the numbers from such different eras is not an easy thing to do.
Note that all of these are players rookie seasons unless otherwise noted.
Ronald Acuña Jr.
487 PA, .293/.366/.552, 26 2B, 4 3B, 26 HR, 64 RBI, 16-21 SB. bWAR 4.1, fWAR 3.7
Ken Griffey Jr.
666 PA, .300/.366/.481, 28 2B, 7 3B, 22 HR, 80 RBI, 16-27 SB, bWAR 5.2, fWAR 5.0
Griffey was in his second year at the age of 20, as he made his debut at the age of 19.
This may be the single guy that Acuña’s numbers are right in line with for an age-20 season, despite the fact it wasn’t Griffey’s rookie year and he had roughly 200 more plate appearances.
Bryce Harper
497 PA, .274/.368/.486, 24 2B, 3 3B, 20 HR, 58 RBI, 11-15 SB, bWAR 3.7, fWAR 4.0
Like Griffey, Harper also came up at 19 years old and this was his second season in the big leagues.
Harper had an excellent season for being 20, but the Acuña season is just on another level.
Mike Trout
639 PA, .326/.399/.564, 27 2B, 8 3B, 30 HR, 83 RBI, 49-54 SB, bWAR 8.4, fWAR 10.0
Trout was a rookie in his age-20 season, but he made his debut at age 19 and really struggled with his first taste of big league action.
If there is one guy on this list that Acuña can’t compare to, it’s the unreal season that Trout posted- a season unlikely to be matched at that age anytime soon.
Miguel Cabrera
346 PA, .268/.325/.468, 21 2B, 3 3B, 12 HR, 62 RBI, 0-2 SB, bWAR 0.6, fWAR 0.8
Miggy had a solid season, but no where near what Acuña put up at the age of 20. They both have some similarity in that they played a large role in a playoff run, but it is Acuña with the clear win head to head.
Andruw Jones
467 PA, .231/.329/.416, 18 2B, 1 3B, 18 HR, 70 RBI, 20-31 SB, bWAR 3.3, fWAR 3.7
Andruw also debuted at the age of 19, but this was his full rookie season.
As good as Andruw was at an early age, Acuña has overtaken him with the best numbers in an age-20 season in Atlanta Braves history.
Alex Rodriguez
677 PA, .358/.414/.631, 54 2B, 1 3B, 36 HR, 123 RBI, 15-19 SB, bWAR 9.4, fWAR 9.2
ARod debuted at age 18, crossed the rookie line at 19, and finished second in MVP voting in his first full season at age 20.
This is the other guy that Acuña’s numbers don’t compare at all to, but it also deserves a bit of an asterisk considering Rodriguez is a known PED user.
Mickey Mantle
626 PA, .311/.394/.530, 37 2B, 7 3B, 23 HR, 87 RBI, 4-5 SB, bWAR 6.5, fWAR 6.6
Mantle made his debut at the age of 19, so this was his second season.
I would give Mantle the edge over Acuña, but unlike Trout the numbers aren’t significantly far off for Acuña.
Al Kaline
681 PA, .340/.421/.546, 24 2B, 8 3B, 27 HR, 102 RBI, 6-14 SB, bWAR 8.2, fWAR 7.3
Kaline debuted at the age of 18 and had his rookie year the following season. His age-20 season was his second full year and he led the AL in hits on his way to winning his first and only batting title.
As great as Acuña was, Kaline gets a clear edge over him.
Frank Robinson
667 PA, .290/.379/.558, 27 2B, 6 3B, 38 HR, 83 RBI, 8-12 SB, bWAR 6.6, fWAR 5.8
Robinson gets the slight edge over Acuña, but at the same time it is fair to wonder what Acuña could have done with 200 more plate appearances.
Juan Soto
494 PA, .292/.406/.517, 25 2B, 1 3B, 22 HR, 70 RBI, 5-7 SB, bWAR 3.0, fWAR 3.7
Note: Soto is in his age 19 season this year. I don’t think there is a ton of debate remaining on Acuña vs Soto for their rookie seasons, but Soto also had a historic rookie year and deserved to be included in this comparison as well.
Conclusion
Acuña had a historic age-20 season. In modern baseball, you can say that only Mike Trout, Al Kaline and Alex Rodriguez were significantly better at such a young age, as well as that Mickey Mantle and Frank Robinson were just slightly better.
Acuña’s special season was even more impressive than what Ken Griffey Jr., Miguel Cabrera, Bryce Harper, and Andruw Jones did at the same age.
That Acuña did special things this year was never a debate, but comparing him to this collection of players really helps to show just how historic his season was and what kind of career arc he could have.