Shin-Soo Choo’s Batting Average on Balls in Play

Shin-Soo Choo is a BABIP wizard. Sort for batting average on balls in play since 2008, and sitting there in second place is Choo. After four years of BABIPs in the high .300s, he dropped back to earth in 2011 but still finds himself above the league norm these days. Even with over 2000 plate appearances under his belt, it’s fair to ask: what does Choo’s true-talent BABIP look like?

Just ahead of him on that list is Austin Jackson, who might fit the high-BABIP ideal a little better — after all, he has the wheels to make infield hits out of grounders to the hole. Choo has some speed, but by Bill James‘ speed score, he’s been slower than league average two of the last three years. It’s not speed that’s powering this train.

Instead, it’s line drives. His career line drive rate (21.9%) is well above the league average of around 19%, and he’s above 22% most years. But it’s not all line drive rate — if you sort for line drives, Choo is 39th since 2008 in line drives.

It’s also about Choo’s batted ball profile. He’s hit 1.32 ground balls for every fly ball so far, and we know that the batting average on ground balls is better than those on fly balls. His 1.25 GB/FB ratio is actually 112th highest since 2008.

If you take his GB/FB ratio, and combine it with his line drive ratio, you start narrowing down his list of comps, though. We’ll cut the list off at 95% of Choo’s contributions in both categories (1.188 GB/FB and 20.7% line drive rate), and there’s a list of 34 qualified batters since 2008 that have done something similar in those two categories. These 34 players have a BABIP of .3217. Choo’s career BABIP is .352. There’s still something missing.

Let’s look at Choo’s work year-by-year. Using slash12’s xBABIP calculator, we can see an interesting trend emerge from Choo’s batted ball mix.

There’s something about Choo’s mix of power and speed, paired with his batted ball angle, which makes him well-suited for good BABIPs. This makes sense intuitively, after all — if you’re a slugger muscling up for fly balls, you’re more likely to hit cans of corn than if you have a level swing designed for line drives. This is how you get a career xBABIP over .335, anyway.

But look closer at the yearly xBABIP/BABIP split, and you’ll see something strange. When Choo was BABIP’ing close to .400, he ‘deserved’ a BABIP closer to his career xBABIP level. He hit more fly balls those days, and fewer line drives. He still ‘should’ have had an excellent BABIP, but maybe not one near .350. Now that he’s hitting the ball on the ground more, and reaching new heights in line drive ratio, though, he ‘deserves’ a BABIP near .350 and is receiving his career xBABIP. It has a nice symmetry to it. The feeling that he was a little lucky before is balanced by the surprise that he might be a little unlucky now.

Still, we wonder what this means for his career going forward. Our own Bill Petti found that BABIP has one of the worst year-to-year correlations of any stat — and that line drive rate had the worst. In his ‘good’ BABIP years, Choo has had a wRC+ around 140. In the ‘bad’ BABIP years, he’s had a wRC+ of 108 and 128 respectively.

Is he really 40% better than league average, or more like 10-15% better? His career xBABIP tells us that his current BABIP is the more likely one, even if his xBABIP this year is much nicer. On the other hand, with his power down below career levels this year, it’s a little unfair to say that he’s a BABIP-dependant player. If he got his power back to career levels this year, he’d be able to show his career wRC+ (131). Well, he just hit a home run today, and with it his up-to-the-minute wRC+ is 135, so maybe all this talk of his BABIP is best left for the fantasy blog.

But you still get the feeling that Shin-Soo Choo’s BABIP will continue to be interesting. I asked Cleveland consultant Keith Woolner about Choo’s BABIP over lunch one day. He smiled and said nothing. Maybe he knows Choo’s true xBABIP?