Starlin Castro finished fifth in the Rookie of the Year vote last year, so we know he handled the jump to the majors well. His current .318 average ranks fifth in the NL, so we know he's having a strong sophomore campaign too. But if we look back throughout baseball history, we find that Castro's first season-plus is actually one of historic proportions.
Using Baseball-Reference's Play Index, a fantastic tool allowing users to sift through an abundance of statistics, we can see just how Castro's early career compares to other players and shortstops throughout history. For the purpose of this post, I used a range of 1901-2011 (modern era).
One of Castro's defining characteristics is his age. When the season began, Castro was the youngest full-time starter in the majors, having turned 21 in March. He has been an everyday player in the majors for over a year at an age when most players are either in college or hoping to get the exciting call-up ... to Double-A. For this reason, I wanted to compare him to other precocious players who made it to The Show at an unusually early age.
First, let's take a look at batting average. In about 1.2 seasons' worth of plate appearances, Castro is batting .306. Among all players 23 or younger throughout history, this average over a player's first two seasons ranks 20th (minimum 800 plate appearances). Just ahead of Castro on that list? Hall of Famers Frank Robinson and Heinie Manush.
When we filter to look solely at shortstops, Castro leaps all the way up to fourth. To clarify: Among all young shortstops (defined as 23 or younger) in baseball's modern era, Castro's batting average over his first two seasons ranks fourth. His .306 average is literally 30-40 points higher than Hall of Fame shortstops such as Joe Tinker, Luis Aparicio and Robin Yount.
The next statistic I wanted to look at was doubles. I was just telling my friend Trevor Sierra the other day that whenever Castro is batting, I feel like he's going to hit a double. You know how when McGwire came to the plate in 1998, you just knew that a home run was coming? Or how when Ichiro is up, you feel like it's only a matter of time until he slaps a single through the infield?
Well, with Castro, he always seems likely to square the ball up and hit it hard somewhere. But since he hasn't developed his power yet, I'm always inclined to predict that his plate appearance will result in a line drive in the gap or down the left field line. Apparently I'm onto something: Among all players age 21 or younger in baseball history, Castro already ranks 11th and is just six doubles away from fifth. Keep in mind that this category is actually weighted against Castro, as he has not actually not yet played two full seasons. In fact, of the players whose stats I'm able to see when I researched this (Baseball-Reference shows the top 20 but wipes out most of the stats of the top 10 unless you subscribe), Castro has fewer at-bats than all but two of them. He's a doubles machine, and he's cranking them out at a pace few have matched at such a young age.
The fact is, a player simply is not supposed to be able to rack up extra-base hits and bat .300 in the major leagues when he arrives as a callow 20-year-old. Succeeding in the minor leagues right around the time one reaches legal drinking age is exceedingly difficult; doing so at the major league level is exceedingly rare.
We obviously don't want to get too far ahead of ourselves. We Cubs fans have had more than our fair share of disappointments over the years, from Mark Prior to Corey Patterson to Dwight Smith. You never know when a player's bubble might suddenly burst, but this we do know: Starlin Castro has burst onto the major league scene in a way that has scarcely been seen, not just in recent years but over the last century.