Gonzalez, Kemp, Bonifacio, Bourn, and Young

What do these fellow batsmen have in common?

• Adrian Gonzalez
• Matt Kemp
• Emilio Bonifacio
• Michael Bourn
• Michael Young

Well, probably a lot, seeing as how they all share a profession, but today let us examine a particularly unique distinction: The fact that they collectively represent the top five BABIPs of the 2011 MLB season.

Let’s find out how much was luck and how much was repeatable.

For this exercise, we will be toying around with FI wOBA (Fielding Independent wOBA) and slash12’s xBABIP.

Before we go any further, it is important to clarify that BABIP — batting average on balls in play — is not purely luck. I am just as guilty as most when it comes to wrongly convicting a hitter or pitcher of Luck Crimes when their BABIP strays from .300, but the truth is a lot of factors play into a player’s BABIP — from changing skill levels to improved defensive alignments (see: Carlos Pena) and so on.

FI wOBA tries to step in the direction of better divining what is luck and what is skill in smaller, single-season-sized BABIP samples. With the five top BABIPs in the league, we have an interesting divergence of inputs which makes for a useful case study.

Here is a look at each player’s data:

Key:

wOBA — Weighted on base average.
FI wOBA — Fielding Independent wOBA.
CaB FI wOBA — FI wOBA using career BABIPs.
BABIP — Batting average on balls in play for 2011.
slash12’s xBABIP — A BABIP regressor based on batted ball types.

Observations:

For each of these five league leaders, their CaB FI wOBA was lower than their FI wOBA. That means that each player would regress offensively if they returned to their career norm BABIPs in 2012 — which is beyond obvious. With FI wOBA, though, we can offer accurate, numerical predictions.

For instance, Adrian Gonzalez, despite having his career-best wOBA in 2011, would actually have had a wOBA beneath his career average (.375) if his BABIP had been at normal levels. Why? Because his walk rate went down as did his home run rate. Nearly the same is true for Michael Young, who had one of his best offensive seasons despite depreciation in other areas of his game, namely his home-run rate and walk rate.

Matt Kemp, on the other hand, had a CaB FI wOBA equal to his real-life wOBA. In fact, his FI wOBA says he should have hit 18 points better than his already gaudy 2012 wOBA. Why? Consider this: He had career highs in home run rate, walk rate, and stolen base rate. His BABIP may have been high in 2011, but his peripherals were just as high.

Using slash12’s xBABIP, we can peer into a more clear picture of future expecations. When a hitter has a BABIP higher than his career norm, it does not automatically imply he is lucky. Perhaps he is hitting more line drives (which can lead to fewer home runs, but more total offense) or more ground balls (which have higher BABIPs than fly balls).

Here is where it gets interesting: Given the preponderance of ground balls and line drives from Michael Young and Emilio Bonifacio, we should expect them to both have higher BABIPs than they actually did in 2011 (thus the green cells in the above chart). This means their hitting profiles suggested wOBAs higher than they their real-world 2011 wOBAs.

Bonifacio (24%) and Bourns (26.6%) had career-high line drive rates in 2011, while the other three had their second-best or third-best career line drive rates. Combined with the other facets of their game, only Matt Kemp would do worse (though still laughably good) if they all maintained those batted ball rates.

Of course, it would be silly to expect consistency in the realm of batted ball rates — they fluctuate wildly (not to mention the possible reporting errors in publicly available data), and compared to walk rates, strikeout rates, and the other inputs to FI wOBA, batted ball rates are simply hard to trust.

Ultimate Conclusions:

Adrian Gonzalez tattooed the ball in 2011. He may not repeat his line drive rate in 2012, but given his still-strong home run per fly ball rate, a decrease in LD% would likely just result in more homers. In other words: His BABIP may go down, but his wOBA should stay near .400, all else equal.

Matt Kemp is insane.

Emilio Bonifacio can repeat his surprisingly successful 2011 season — it’s within possibility — but unless he is suddenly seeing the ball better, resulting in more line drives and fewer fly balls, he will need to change his approach (more walks, fewer Ks is the ideal solution).

Michael Bourn has more troubling signs around him. If he cannot sustain his crazy line drive rate (and that seems unlikely), then his offense will fall back on the haunches of a near-career-low walk rate, a high strikeout rate, and a disappearing home run per fly ball rate. Without BABIP luck in 2011, Bourn would have been just a pair of legs without a base to steal.

Michael Young has the ability to hit a 22% to 25% line drive rate, and unsurprisingly has a .338 career BABIP. He probably will never repeat nor improve upon his 2011 BABIP and line drive rate, but his offense still should be good — though still reliant on the whimsy of batted balls.

But these days, what isn’t?