Baseball-Reference is one of the best websites ever created.
One feature of Baseball-Reference is similarity scores, a statistic developed by Bill James in the 1980s.
Similarity scores are purely statistical analyses. To see the comprehensive formula for similarity scores, go to https://www.baseball-reference.com/about/similarity.shtml.
Ronald Acuña Jr. has gotten off to an explosive start to his career. Through his age-20 and age-21 seasons, Acuña has been named NL Rookie of the Year, an NL All-Star, a Silver Slugger, and has placed 12th and fifth in NL MVP voting. Acuña nearly recorded the first 40-homer and 40-steal season in 13 years, and he led the NL in runs in 2019. With a player as good as Acuña at such a young age, it can be fun to take a look at other players who took Major League Baseball by storm.
Here are the 10 most similar batters to Ronald Acuña at age-21.
A legend with the Orioles and Reds, Robinson was a two-time MVP, winning the NL MVP at age-25 and AL MVP at age-30. Robinson is a member of the 500-homer club, and he posted an otherworldly 154 OPS+ during his 21-year career. Robinson finished his career with four seasons with an OPS over 1.000, a number that Acuña could approach if his plate discipline improves.
Cabrera is still in the majors, but his best days are behind him. Cabrera did not win Rookie of the Year at 20, but he did have a World Series ring on his finger. Cabrera began his career by receiving MVP votes in 14 consecutive seasons including the 2012 and 2013 MVP trophies. Cabrera owns a Triple Crown, and he could get into the 3,000-hit or 500-homer clubs with two injury-free seasons.
One of the most feared power hitters of the 2010s, Stanton mashed 308 home runs in the decade despite missing an average of 45 games per season. Stanton was the 2017 NL MVP after finishing runner-up to Clayton Kershaw in 2014. Stanton has been inconsistent at times due to injuries and strikeout problems, but Stanton has plenty of juice left in the tank with the Yankees.
The first of a handful of former Braves, Aaron laid waste to the National League for 23 seasons. Aaron was the 1957 NL MVP, and he owns the eighth-most MVP shares in MLB history. Aaron holds the record for career RBI and total bases and held the home run record from April 1974 to 2007. Aaron racked up 3,771 hits and added 240 steals for good measure.
Upton has posted 13 solid years in the bigs, including a pair with the Braves in 2013 and 2014. Upton has been wildly inconsistent for the most part, posting four All-Star nods and four seasons with MVP votes, but he has never been able to post back-to-back seasons with either. Upton had three-straight 30-homer seasons before playing just 63 games in 2019.
Conigliaro had a promising career debilitated after being hit by a pitch in 1967, damaging his eyesight and preventing him from a full career. He holds the record for most home runs by a teenager (24) and led the AL in home runs in 1965. Conigliaro finished his career with just 876 games played, but he was a sensation in the 1960s.
A long-time Brave, Mathews is a member of the 500-homer club and a two-time World Series champ. From age-21 to age-23, Mathews averaged 43 home runs, 113 RBI, and an absurd 1.025 OPS and OPS+ of 171. Mathews never hit the heights of his youth again, but he finished his career with a pair of runner-up finishes to NL MVP.
The modern-day best player in baseball, Trout has been a dynamo for a decade. His Baseball-Reference page is littered with bold text (indicating that he led the AL in a stat) including a ridiculous six times leading the AL in OPS+. Trout is a three-time AL MVP and has four runner-up finishes in addition to a fourth-place finish in 2017.
A two-time All-Star before his age-21 season, Harper took a step back at 21 before decimating the league in 2015. Harper was the NL MVP in 2015, leading the NL in runs and home runs while leading all of baseball in on-base percentage, slugging, and OPS. Now 27, Harper is one of the best power hitters in baseball and should get his third-consecutive 30-homer campaign in 2020.
The list ends with another Brave in Horner. While not as famous as the nine above players, Horner was the 1978 NL Rookie of the Year (after being the first pick of the 1978 MLB Draft and spending no time in the minor leagues) and made the All-Star Game in 1982. Horner received MVP votes three separate times and had a trio of 30 home run seasons, and he has one of the 18 four-homer games in MLB history. By 1989, Horner announced his retirement after a collusion scandal barred Horner from receiving a contract at his value.