How about we learn a bit about baseball?
Some of you are very fluent on the advanced stats, but some of you aren't and that's okay. How about we discuss an easy one to understand: Batting Average on Balls In Play (BABIP), which measures the percentage of balls in play that go for hits.
A ball is considered in play when the plate appearance ends in something other than a strikeout, walk, hit batter, catcher's interference, sacrifice bunt, or home run.
A lot of people use BABIP to determine whether or not a pitcher or hitter's successes or struggles are inflated by "luck." I think there's some value to BABIP, but it isn't one of my favorite sabermetric stats.
Thirty percent of balls in play become hits - since 2000, the Major League BABIP is .298 - and the idea, to some, is that over time most players will regress or progress to that number. The suggestion that most players are equal in this regard is the part with which I take exception concerning this stat.
For instance, if Player A has a BABIP of .364 at the All-Star Break, ardent subscribers of BABIP normalization will tell you that he's perhaps on the precipice of a slump due to his abnormally high BABIP. The theory can also be applied season-to-season. Let's say Player B hit just .260 in 2015, partially due to an abnormally low .245 BABIP. BABIP loyalists will tell you that Player B is due for a bounce back year based on the pretense that he was a victim of a "bad luck" BABIP.
In both cases, the same logic can be applied to pitchers.
With all that said, I don't particularly buy into the BABIP theory to its full extent.
In general, I'm not a big fan of assuming trends for players based on league averages. The reality is, most players are not league average, but above or below that line.
I think that it is better to compare players to themselves and not a league average for this particular metric. All players are different with a different set of skills, so if comparisons are to be made, I feel like it is more telling to compare them to themselves.
Let's take Nick Solak, who is really fast. It would make sense that he would have a higher BABIP than a slower comparison because he'd be able to beat out a higher percentage of ground balls. So, would it really make sense to compare Solak's BABIP to, let's say, Jeff Mathis?
On the mound, talent is also a part of the discussion. If we believe that weaker contact produces fewer hits, which is supported both statistically and logically, and that better pitchers are more capable of generating weaker contact, then it would make sense that better pitchers have a more favorable BABIP.
Those who swear by BABIP live under the assumption, it appears to me, that all balls put in play are equally. A 105 MPH rocket off the bat stands a far greater chance to be a hit than an 85 MPH bouncer. Better pitchers are going to induce more of the latter than the former, thus grouping them in with lesser pitchers who get hit harder doesn't seem prudent. This is another reason why comparing players to themselves, or, at least, to those with a similar skill-set or skill level, appears to be more appropriate.
Defensive alignment also impacts these numbers. Not every player hits into the same defensive alignment and therefore comparing guys who have different strategies played against them makes it tough.
A batter that constantly hits against a shift is likely to have a lower BABIP than someone who doesn't. When a defense isn't able to allocate their fielders in a concentrated area, they'll have a tougher time turning balls put in play into outs.
Comparing players who face the same defensive alignment is more practical than guys who face totally different fronts.
A better defensive group will allow less hits, though, neither the hitter, nor the pitcher, have control over that, specifically. A pitcher is likely to allow a lower BABIP with a good defense behind him than with a bad defense behind him. The same logic can be applied for a hitter.
The luck element involves bloop hits and infield singles that are poorly struck but are positioned perfectly. On the flip side, there's always that scorched line drive hit right to someone. In theory, all this will even out in the long run but it typically takes some time for that to happen.
As is the case with all advanced stats, they tell a story, but not whole the story. BABIP is an interesting thing to assess, but remember to consider context and recognize a player's skillset before jumping to regression or progression conclusions for this particular metric.
2019 BABIP Notes, Hitters
Highest BABIP (MLB): Yoan Moncada, .406 (White Sox)
Lowest BABIP (MLB): Jurickson Profar, .218 (Athletics)
Highest BABIP (Rangers): Danny Santana, .353
Lowest BABIP (Rangers): Rougned Odor, .244
2015 BABIP Notes, Starting Pitchers
Highest BABIP (MLB): Jon Lester, .350 (Cubs)
Lowest BABIP (MLB): Justin Verlander, .219 (Astros)
Highest BABIP (Rangers): Brett Martin, .340
Lowest BABIP (Rangers): Rafael Montero, .269
