Marlins outfielder Christian Yelich is only 24 years old, but he has already scored a long-term deal that will keep him in Miami through 2021 (or the team's next fire sale). He's one of the growing number of young stars that teams like to lock up early, which, at an average value of $7 million per season, seems like a smart move for the Miami Marlins after three successful years in the majors.
How has Yelich achieved success? Simple: a high batting average on balls in play, or BABIP. He has batted over .350 on balls in play in each of his three major league seasons, and owns a career .365 BABIP. For comparison, Ian Kinsler owns a career .287 BABIP. Yelich has really been sitting pretty.
A lot of times, BABIP is discounted as a mere product of luck; if a hitter posts a high one, it is likely to drop at some point, and vice versa. This is true, but only to a certain extent. Don't expect Andrew Romine to sustain a .450 BABIP if that's what he has at the end of May.
However, hitters have been shown to exert a small level of skill in the BABIP category. This is evident with former Detroit Tigers center fielder Austin Jackson, who even after a couple of sub-par years since leaving Detroit owns a .352 BABIP in over 3,000 career a-bats.
Yelich has less experience than Jackson, so it's a little more dangerous to assume that he will sustain his BABIP. After all, we spent years wondering if Jackson's would ever regress closer to the league average (around .300).
Let's create a quick confidence interval to find out what range we're 95 percent certain his "true" skill in this stat is. Using a given proportion of .365 in a sample size of 1298 career at-bats, a one-proportion z interval turns up the range of between .332 and .398. For those who have forgotten their college statistics class, we shouldn't expect Yelich's BABIP to ever deviate outside that .332 to .398 range, meaning he's just one of those players (like Jackson) who can exert some skill over his career BABIP.
This makes sense when you consider that, in many ways, Yelich is like Jackson. Yelich has a career line drive rate of 22 percent, while Jackson's is 23.7 percent. Both of them have earned a reputation for getting out of the batter's box quickly, which surprisingly has not led to a high rate of infield hits for Yelich (6.1 percent on his career, compared to an MLB rate of 6.6 percent). Yelich attempts to steal a little less than a young Jackson did, but he has a slightly higher success rate. He also walks more, but his power numbers are similar to what Jackson posted during his heyday in Detroit.
All in all, it's obvious why the Marlins wanted to lock up Yelich. He's a solid defensive player (better in left field than center) who also happens to have a repeatable skill for getting on base when he puts the ball in play. Don't be surprised if he's a thorn in the side of National League pitchers for years to come.