Why we overvalue blocking in the postseason

FanGraphs had a good piece recently on passed balls and their ilk, the wild pitch, and that the general trend in baseball is that they are up. It’s been on display in particular this postseason, with the likes of Yasmani Grandal having two passed balls in a game, and the league averaging more than one wild pitch per game.

It’s another case of “we know why this is happening, but is that OK?” Baseball is beleaguered by harder stuff and more breaking balls, and especially sliders. As long as pitchers are throwing harder and faster breaking pitches, which often require pitches in the dirt, then there will be more wild pitches and passed balls. It looks ugly, frankly.

The mathematical case for this is clear. Would you rather throw more effective pitches, which comprise every concrete event in the sport, or throw a sub-optimal repertoire to bring better catching into the fold? You know the answer.

Fans... they don’t really get that. A lot of fans see defense—I would say that was the case with the front office as well, until recently—as a series of binary events. There is a play that is made toward a particular fielder, and that fielder either makes the play or doesn’t. That’s the logical basis for fielding percentage, which tried to answer the question of how good a fielder was.

What was discovered not too long ago is that defense is largely outside of view, that if we don’t have comparable players to look at in concert, then we would never answer the actual defensive question: “How many more plays do they make versus the replacement level or average player?”

That’s a harder question to answer, mostly because if you see a grounder squeak through the infield, it was hard (until recently) to say whether that play would have been made if it was a different player. What people largely see are mistakes, or lack thereof. If a player is a -20 DRS defender but has a high fielding percentage; well, that gets lost in the shuffle.

So, when we see blocking in catching, we see the raw numbers. When fans saw Gary Sanchez allowing an inordinate amount throughout the last two years, they saw a player who fundamentally failed at their position. It missed, though, the necessary context that the Yankees had the highest slider percentage in baseball; and, crucially.... blocking isn’t all that important.

That sounds like sacrilege, until you put it on paper:

The bad teams are pretty bad, and the good teams are OK, which means the actual histogram-like distribution is pretty thin as well:

Nearly half of the league finds themselves in the (-0.5,2.5) set, and two thirds are within the (-3.5, 2.5) range. That is less than a win, and even the upper bounds is just a hair beyond.

There’s even some weak, positive relationship between blocking runs and fastball percentage:

When it comes to velocity, you get the same type of weak correlation:

What this means is that one in ten (I always warn, this is back-of-the-napkin math) of team blocking runs can be explained by the amount of fastballs thrown, and how fast they are thrown. If Sanchez has 20 passed balls, then a few can be explained by those. You probably wouldn’t notice that, so if there is a league-wide increase in passed balls, then the reason for an increase would be largely imperceptible.

But, then again... the effect of passed balls are imperceptible, which is the point. If the best blocking team and worst are separated by about a win, then the difference is maybe two passed balls per month.

All eyes are on the postseason for a reason. Missing from all of this is that leverage does play a role, so if you allow a passed ball in the bottom of the ninth in a tie game; well, that could be a quarter-win right there. And when you’re dealing with championships, you could sacrifice a large chunk of championship probability on what is considered a simple mistake.

That is to emphasize that passed balls are important. If the trend progresses and it continues to increase, then the team that seizes upon this market inefficiency with better blockers could nab a half-win or so, which isn’t nothing. And sometimes in the postseason, fundamentals could make all the difference. I would just warn to keep passed balls within that larger framework, because for the most part, the highest correlation to winning in the postseason is a) luck, b) strikeouts, and c) (in today’s game) home runs.