The slash line on a ground ball this season is .234/.234/.254. The slash line on a fly ball this season is .231/.226/.625. The slash line on a line drive this season is .727/.723/.981. So, obviously, you just want to go and get any player that is hitting frozen ropes all over the park.
Line drives are also highly correlated with a great batting average on balls in play. That led slash12 to originally create an xBABIP calculator based on batted ball mix, and then Jeff Zimmerman to update that calculatorfor our use this season, considering our lower run environment and the added use of the shift this year. Using the new xBABIP calculator, here are your least lucky players.
So, these guys are hitting line drives and should have better BABIPs. They are rock solid buy lows then, right?
Not so fast. It’s still not that easy.
Line drives have a terrible year-to-year correlation (about .5), so it’s hard to find a guy that consistently hits frozen ropes like Joey Votto does. That’s why he’s Joey Votto and we’re not. The other problem is classification. Have you ever seen the designations on batted balls in the FanGraphs box scores? Here’s a random game between the White Sox and Blue Jays — you’ll see Fliner (Fly), Fliner (Liner), Fly, and Liner designations, and that’s not even counting the ground balls.
Watch a game and try to distinguish between a Fliner Liner and a Fliner Fly and you’ll quickly know the difficulty in using those numbers to make decisions. Colin Wyers wrote about the stringer bias and problems in batted ball data and might say, even though the people making the LD/GB/FB decisions are trained to do what they do, those designations are not as good as a machine’s might be. What if the guy making decisions about line drives in New York is giving Russell Martin and Ike Davis too many line drives when they should be Fliner Flies?
There is one batted ball decision that should be fairly bias-free — the infield pop-up. The pop-up doesn’t look like a fly ball or a line drive, so it should be fairly easy to describe. And the batting average on a pop-up is near zero. Ari Berkowitz on Beyond the Boxscore did some work looking at the correlation of different metrics that included pop-ups, and he found that fly balls per pop-up correlated pretty well with batting average on fly balls. This is another way of saying that if you hit the ball hard and in the air, you’re good. Look at his list of leaders in FB/PU, and of course Joey Votto sits on top, with great players littered throughout. There are some good implications for Austin Jackson and Shin-Soo Choo, too.
What if we combine these two types of analysis? We might double-count guys that don’t hit the pop-up (infield fly balls are already in xBABIP), but we might also emphasize the batted balls that are easiest to distinguish from each other.
Sort your top 20 unluckiest players by xBABIP and then sort those by FB/PU, and your most powerful, least lucky players zoom to the top. Drew Stubbs is one of your new leaders (16.7 FB/PU), with Justin Morneau and Adam Dunn right behind him. The other guys with double-digit FB/PU numbers are Eric Hosmer and Cliff Pennington. They all seem like reasonable players to target if you’re looking to buy low on batting average.
But there’s one name that trounces them all. He’s hitting a whopping 34.5 fly balls per pop up, and he’s got the second-most line drives in the top twenty unluckiest by xBABIP. He’s young and he’s got developing power. He’s got a decent BABIP right now, but he should have a great BABIP. And if he had a great BABIP, he would suddenly be a great addition to a lineup in any sort of league.
His name is Freddie Freeman.