Okay, first a caveat: I go to a few Oakland As games every season, but I’m not a baseball fanatic; I married into the game. My wife agreed to move with me to Chicago 20 years ago when I found an apartment within walking distance of Wrigley Field. Proposing to her also helped, but I’m not sure which was the more important factor.

So I’m not a baseball expert by any means, but I still found this article about how “The Rockies Believe They Have an Unbreakable Code,” and more generally how signaling is turning into a point of contention over who makes decisions about pitches, pretty interesting.

Last Sunday, the Washington Nationals broadcast noticed an unusual card sheathed in clear plastic on a wristband that was adorning the left arm of Rockies catcher Chris Iannetta…. The wrist card wasn’t just something the Rockies implemented Sunday. Iannetta has worn the card since the Rockies’ season began in Arizona….

While other teams might have already done something similar, this wristband — or, at least the scope of it — seemed to be unusual in nature. And with the amount of information available in today’s game, when it’s possible to know every batter’s performance against every pitch type in every count, I have wondered if teams would try and get more information to catchers and players on the field.

Mariners’ outfielders are carrying cards in their back pockets to help with positioning this season. In college baseball, the coaches — lacking the trust in their young battery — often call the vast majority of pitches, which can slow things down.

So what’s on the card?

Iannetta said the information is mostly related to controlling the running game, and he explained some of the mechanics of the process. “It’s just a random three-digit number that corresponds to a sign and then we have 10 different cards with random numbers,” Iannetta said. “As soon as they [the MASN broadcast] zoomed in… we heard about it and switched cards immediately. We switched to a different card with a whole new set of numbers. There’s no way to memorize it. There’s a random-number generator spitting out a corresponding number [for the cards], and the coaches have the same cards.”

So the signals are no longer part of a language that each team possesses, or that evolves between specific pitchers and catchers; it’s now more like coded signals in the military.

What’s also interesting about this, though, is that it foreshadows a change in who control the calls, the catcher or the coaches.

In college, the coaches already do so, mainly to keep the game moving. But in major league baseball, there’s a potential competition between two very different kinds of expertise.

On one hand, the catcher possesses a lot of on-the-ground knowledge. They know how confident each hitter is when they come to the plate, can observe how forcefully they’re hitting, whether they’re in the zone or distracted, etc. They also know their pitcher’s performance. “On any given night,” the article says, “the pitcher is going to have a different feel, a different comfort level, with certain pitches that will be unique to that contest.” Put that together, and a good catcher can really shape the play.

On the other hand, coaches now have a staggering amount of data about players, and there’s a temptation to use that to shape the game by allowing coaches to call more of the pitches.

But as the signaling system gets more complex, and you can change it up more often, there’s an opportunity to either use it to deliver more information to catchers, or to displace the knowledge of catchers entirely and rely on big data.

What’s important here is that it’s not that one form of knowledge or expertise is necessarily superior to another; they’re probably best seen as incommensurate, as forms of knowledge that are so different it’s like comparing apples and manta rays. But you can imagine coaches deciding that they want more control over the game, or thinking that big data will let them use less experienced catchers, or simply being super-impressed at the statistics and all the cool things you can do with it. In order words, adopting what looks like a data-intensive and rational system for reasons that actually aren’t that rational.