Does One-Knee Catching Lead to More MiLB Wild Pitches?

Whenever I have studied the effects of the rise of one-knee catching in the major leagues, I have tried to emphasize that the data I’ve studied relates to the major leagues.

On social media, I have been asked on multiple occasions what this means for younger catchers. Can high school catchers adopt one-knee catching stances and see the same benefits (better pitch framing) without any significant downsides (worse performance in blocking pitches or throwing out baserunners)?

And the answer remains: I don’t know. Catching instructors may have strong opinions, but I’m not a coach. I’m just relaying what I can find from the data.

I’ve looked at the statistics of MLB catchers, both on an individual catcher level and on a league-wide basis, and I’ve been unable to find an example of how the rise of one-knee catching has led to an increase in passed balls (this year could end up seeing the lowest passed ball rate in MLB history), wild pitches (this year’s wild pitches are down and are at historically low rates) and stolen base rates (this year has also seen one of the lowest stolen base rates in MLB history).

But the same statistical approach that I used recently at the MLB level can be brought to the minors. And in doing so, I can say when it comes to how the rise of one-knee catching has affected minor league catchers, the answer is, even after looking at statistical data, I still don’t know, but the data does not follow the same trends as the major leagues.

Here’s what we do know. Unlike at the MLB level, the passed ball rate in the minors is up slightly from before one-knee catching stances became popularized in 2019-2020. In 2017, 2018 and 2019, there were .12 passed balls per game for MiLB full-season clubs. In 2021 and 2022, there were .14 passed balls per game. That’s a rise of roughly 2.8 passed balls per team per season. That may seem to be a small number, but it is also the highest passed ball rate in the 2010-2022 period we studied.

The number of wild pitches has also increased. In 2016-2019, the wild pitch rate hovered between .61 and .64 per game. In 2021 and 2022, it rose to .76 wild pitches per game. That is the highest rate in the 2010-2022 period we studied as well.

So if one wants to argue that the rise of one-knee catching in the minor leagues has led to an increase in wild pitches and passed balls, there is some data to buttress that argument. The same cannot be said at the MLB level.

It’s possible that other factors are at play. There was no minor league season in 2020, and it’s possible that the loss of development time in 2020 could play a contributing role. The reorganization of the minors for 2021 eliminated short-season and rookie ball, which reduced the average age of Class A position players. That could play a role as well. The rate of errors per game also increased in 2021 and 2022 in comparison to 2016-2019, which may add some credence to that theory. There was an average of .89 errors per game in 2022 and .93 errors per game in 2021. From 2016-2019, the average error rate was .86 errors per game and it was never higher than .88 errors per game.

And since MiLB is used for development, it is also possible that catchers are struggling to receive in part because they are being taught to focus on framing borderline pitches. One of the ways catchers learn where their limit is between where they can try to quietly receive a borderline pitch and where they need to focus more on simply catching the ball (by for instance flipping the glove from thumb down to thumb up on a low pitch) is by repetition. 

But the data does show that wild pitches and passed balls have increased at the MiLB level since one-knee catching became popular.

No attempt has been made to try to quantify the effect of one-knee stances on stolen bases in the minors, because the basic rules have changed. In the minors, pitchers are now restricted to two pickoff throws (a third unsuccessful throw leads to an automatic base for baserunners). Also, the rise of the pitch clock has given basestealers a head start at times, as some have found that they can take off as the clock ticks to zero, knowing that the pitcher has to either deliver the pitch or face an automatic ball.

That has led to a massive rise in the number of stolen base attempts in the minors and a decrease in the caught stealing percentage, making any comparison of stolen base rates from the 2010s to 2022 virtually meaningless.