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Jason Castro and the unknown effect on Astros pitchers

Jason Castro is a great defender by every available metric. But the Astros starters pitched worse with him, and the Astros made no effort to retain him. Why?

MLB: Houston Astros at Seattle Mariners Joe Nicholson-USA TODAY Sports

There is so much that the public, even the smart public, still doesn’t understand about baseball.

A few years ago, the saber crowd got into a tizzy when it was revealed how much impact a catcher can have by receiving the ball quietly, called “presentation” or “framing.”

And now, we pat ourselves on the back because we have so much understanding! We can say with confidence that Yasmani Grandal or Buster Posey or Hank Conger or whoever is the best defensive catcher in baseball because framing.


Not to discount the value of the discovery, because it was an amazing advance in catcher defense that cannot be under-stated, but there are still some pieces missing from the catcher puzzle.

Game-calling. Pitcher handling. Pre-game preparation. Knowledge of batter tendencies. Knowledge of umpire tendencies. Ability to apply said knowledge in-game. Ability to recognize when such knowledge needs to be discarded in the interest of game flow or pitcher comfort or batter discomfort. Ability to get along with your pitchers. Ability to get along with your umpires.

We still don’t fully understand catcher defense, and perhaps the things mentioned above cannot be quantified in such a way and it will remain the last great elusive frontier of projection systems.

How do you quantify psychology and personality, anyway?


I’m warning you now - I am drawing no conclusions in this article. I refuse to speculate on the impact of yet-undefined aspects of catcher defense.

I am readily acknowledging that sample sizes apply, or that data inclusion or exclusion can present results that might lead to incorrect assumptions.

I merely post this article to point out an oddity that perhaps in some small way explains the Astros’ decision to not sign catcher Jason Castro to a contract extension.

This is not a hatchet job against Castro. I am careful to not write negative articles about players unless I have data to back up conclusions. I am making no statement whatsoever about the player or the team’s reasons for parting with him.

I’m merely serving up a plateful of food for thought.


Castro recently signed a Free Agent deal with the Minnesota Twins, for far less money per year than will be owed to recently-acquired catcher Brian McCann.

Castro was drafted and developed by the Astros, suffered through the lean years, was behind the plate for two playoff runs, and perhaps most importantly, is graded as one of the best pitch-framers/presenters in the game by all publicly-available metrics.

So why didn’t the Astros re-sign him, instead opting for older, more expensive, and arguably worse-defensive McCann?

I dunno, but here’s a table that’s at least interesting.

Pitcher career ERA with and without Castro:

From the table, I removed all players who caught less than twenty innings with a particular pitcher, to remove the uncertainty inherent when a catcher and a pitcher work together for the first couple times in a game.

I also want to note that of all the pitchers, Fister’s numbers here are unfair to Castro, since he inherited Fister when he was clearly a shell of the pitcher that he had been earlier in his career.

Again acknowledging sample sizes as standing firmly in the way of drawing any conclusions, this table is at least a little eyebrow-raising.

Is there smoke here? Is there fire? I don’t know. I can’t say that there is. But I also can’t say that there isn’t, which is why I decided to post it.

So what, then?

The point of the table is to illustrate that despite all of the public metrics and framing numbers screaming that Castro is among the elite defensive catchers in the game, most of his pitchers performed worse with him behind the plate than they did on average with all other catchers.

Weird, huh?

Because so much is un-quantified, we don’t really know what this means, if anything.

It is possible that Castro struggled with game-calling, and asked for the wrong pitch at the wrong time more often than his counterparts. Public metrics don’t account for this.

It is possible that it is difficult to decipher the signs he puts down due to some quirk of timing or anatomy.

It is possible that the umpires don’t like him.

It is possible that his pitchers don’t like him.

It’s possible that his pitchers and the umpires LOVE him and this is a data fluke, just another eye-rolling “small samples are garbage” thing.

It’s possible that Castro is the only catcher so far who can consistently block a Collin McHugh curve ball.

We don’t know.

What we do know is that in the past, most of the Astros starters have performed significantly better without him. In the cases of McCullers and Fiers, a full half a run better.

If there is smoke, and if there is fire, the Astros probably know about it, because their methods for collecting and processing information far outstrips what the public can achieve. If so, it would explain their apparent non-interest in retaining Castro’s services, for sure. Nothing else seems to.

But at the same time, maybe he just really wanted to test Free Agency. Players do that.


Castro probably will only help Minnesota’s starters, who struggled as a unit last season. He may be very successful. Maybe the Astros made a mistake.

But maybe they didn’t.

The one story line that I will be watching closely in 2017 is if the Astros’ returning starting pitchers make significant improvements to their ERAs with McCann and Evan Gattis sharing receiver duties, even despite the hit in framing ability.

If that happens, it’s a shot across the bow to the spreadsheet crowd. Folks such as me.