Do One-Knee Setups Hinder A Catcher's Blocking Ability?
Barring the unexpected arrival of shocking new information, this is the last time I’m going to study the differences between one-knee setups and traditional setups (with both knees off the ground) for MLB catchers.
Each of the past three years, I’ve attempted to study the difference in blocking rates between major league catchers who use a one-knee setup and those who use the traditional crouch with both knees off the ground.
Here's the first study we did at Baseball America. And here's the second, which focused on the league as a whole.
These studies are in large part me trying to answer the question that you hear on broadcasts all throughout the season, where analysts wonder why catchers would be so bold or so lazy as to set up in a one-knee setup with runners on base. I wanted to know if there is any data to support such statements. Do MLB catchers who put one knee on the ground in their setup struggle more to block pitches than those who use a conventional setup?
As every study we have done at Baseball America has spelled out, the simplest counter argument is the strongest one. If one-knee catching actually was detrimental to winning ball games, MLB teams wouldn’t do it. And the never-ending trends toward one-knee catching at the big league level are a clear indication that MLB teams have found that one-knee catching is a superior way for most catchers to receive pitches.
At this point, no one seems to argue the point that the one-knee setup helps MLB catchers better frame pitches and present them for umpires. That was the driving reason why it has become popular around the majors.
The long-running concern, however, has been that catchers are trading a benefit (better framing) for a drawback (lessened ability to block pitches).
At this point, I’ve seen enough. I’m calling it. I’ve tried to look at this in every possible way, and I’m confident in saying that at the major league level, I cannot find any evidence that one-knee catchers are more prone to allowing wild pitches and passed balls than catchers who use a traditional setup. I will note that this is at the MLB level. It would be much harder to come by the data to study this at the amateur levels. So for now, all we can say is this is what's true in the major leagues.
Thanks to Statcast’s new catcher blocks metric, there’s new information to analyze this year. We looked at all 66 catchers who qualified for Statcast's blocks leaderboard. To begin we classified every MLB catcher who qualified for MLB’s catchers' blocking leaderboard by using a one-knee setup, a traditional crouch (with both knees off the ground) or a hybrid approach where they switch between the two setups. And then we can see how those catchers fare at blocking as measured by Statcast.
To determine how to classify each catcher we looked at the situations where failure to block a pitch would be the most devastating. For all these catchers, we looked at at least five pitches where they were forced to block a pitch with a runner on third base. We noted whether they set up with a one-knee setup or in the traditional crouch. If a catcher varied between the two over that five-pitch sample, we then watched every block attempt they had in 2022 with a runner on third base to determine if they were a true hybrid or a catcher who had a clear preference.
Here are the top 10 catchers in blocks above average in 2022.
So the best blocker in baseball last year, Adley Rutschman, used a conventional setup. But five of the next six best blockers used a one-knee setup and another used both.
Here's a look at the worst blockers in the majors last year:
So what we find again is a mix of styles. The worst two blockers in baseball last year used a conventional setup, but the next four worst all were catchers who set up on one knee. This tells us a little, but not all that much. It tells us that it's possible to be an excellent blocker from either setup or a terrible blocker from either setup.
But let's look at all 66 catchers who qualified and see what that tells us.
|Setup||No. of |
Blocks Above Avg.
The number of catchers using each style is useful information. When we first studied this in 2021, we looked at the 54 catchers who caught 20 or more games in the majors in 2020. At that time, the number of one-knee catchers and conventional catchers was split almost equally. Now, there's a clear shift to more catchers using the one-knee approach. It's worth noting, as we have before, that the number of passed balls and wild pitches per game at the MLB level has dropped over the past three years, during a time where more catchers were adopting the one-knee setup, which is a strong indication that one-knee catching does not lead to more wild pitches and passed balls.
But what we find is one-knee catchers average .49 blocks above average per catcher. The conventional setup catchers average .42 blocks above average per catcher. The hybrid setups are the notable standouts here, at 3.6 blocks above average per catcher. When we last studied this in 2021, the hybrid catchers struggled much more in blocking, so with the small sample size, we're not going to make sweeping generalizations, but it is notable that the five hybrid catchers range from excellent blockers (Tomas Nido and Tucker Barnhart) to around average (Tyler Heineman, Martin Maldonado) to slightly below average (Reese McGuire). There were no truly bad blockers among the hybrid setups.
But this isn't trying to argue that one-knee setups allow catchers to better block pitches than conventional setups. It's asking the question of whether they can block as well. And in this case, it's hard to argue otherwise. The numbers here actually state that the one-knee catchers do a slightly better job of blocking than those with conventional setups.
And if that's the case, then your broadcaster's favorite five-minute sermon after any passed ball or wild pitch doesn't make any sense. Because if one-knee MLB catchers can block as well as catchers with a conventional setup, than the arguments against one-knee catching become pointless.
When it comes to pitch framing, the evidence is quite clear that one-knee setup catchers steal strikes on the edges of the strike zone better than catchers in conventional setups. Here's the leaderboard and bottom 10 as measured by Statcast's Framing Runs Above Average.
|Player||Setup||Framing Runs |
And here are the overall numbers for the 66 catchers we studied.
|Setup||No. of |
|Framing Runs |
When it comes to framing pitches, those who use one-knee setups and those who use hybrid setups (which means one-knee setups consistently when no one is on base and some of the time when they are) are getting many more borderline calls than those who use a conventional setup.
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That does leave one other avenue to explore. With stolen bases numbers expected to rise this year due to rules changes that are meant to encourage more steals, does one-knee catching hurt MLB catchers' ability to throw out basestealers?
Now this is a tricky stat to study, because catchers are only part of any attempt to slow a basestealer. A pitcher who is slow to the plate can defang the best throwing catchers, while a pitcher with a good pickoff move and a speedy slide step can give a catcher with a modest arm and a slow transfer a fighting chance.
So instead of studying caught stealing rates, we're going to just look at the Statcast average pop time to second base for those 66 catchers in the study. There are aspects this doesn't cover. An inaccurate but fast throw will show up well in these measurements while an accurate but slow throw won't. However, in-game pop time is useful at measuring both a catcher's transfer and arm strength, so it should provide insights on whether a one-knee setup slows down a catcher's ability to throw to second.
|Best Pop Times|
|Player||Setup||Average Pop |
|Worst Pop Times|
|Player||Setup||Avg. Pop |
Time to 2B
We don't have to go overboard on making assumptions here. J.T. Realmuto's arm and exchange were excellent long before he adopted a one-knee setup. Going to a one-knee setup didn't make him a great thrower, but it also clearly hasn't hindered him. When we look at the 66 catchers as a whole, we again find little difference.
|Setup||No. of Catchers|
Time to 2B
It's hard to find any dramatic differences here. But that's again buttressing the conclusion of this study. No matter what way you look at this, it is hard to find any clear advantages catchers using a conventional setup are gaining over their one-knee brethren. And we see a very clear and glaring difference in how one-knee catchers frame pitches when compared to those with conventional setups.
So the next time you hear a broadcaster complain about a one-knee catcher's unwillingness to focus on the importance of pitch blocking you'll know better.
To help others who may want to study this further, here are the stats for all 66 catchers.
2B Pop Time
If you are wondering why Blocks Above Average does not add up to zero, it is because the catchers who did not have enough blocks to qualify are generally well below average. The 66 catchers who qualified for the blocks leaderboard as a group were 46 blocks above average. The 53 who did not qualify were -43 in blocks above average. The missing -3 blocks are the rounding errors from converting decimals to whole numbers for blocks above average.
For these purposes I am counting Sean Murphy as a one-knee catcher. On July 30, he did use a traditional setup for two block attempts with a runner on third. He allowed a wild pitch on one of those two pitches that caused a run to score. He then used one-knee stances with runners on third base for the remainder of the season. Of his 17 blocks or attempted blocks with runners on third, 15 were while using a one-knee setup.
Austin Hedges also counts as a one-knee catcher. He had 21 block attempts with a runner on third. On 20 of them, he used a one-knee setup. On one, he used a traditional crouch. He allowed two wild pitches that allowed a run to score, and one of those two runs came the one time he used a traditional crouch in that situation.
Will Smith and Andrew Knizner are one-knee catchers, but with a slightly different setup. The two do not put their knee down until after the pitcher has begun his delivery.
Yadier Molina was classified as a one-knee catcher. He kicked one leg out in his setup with runners on third. Usually he had the other knee on the ground, but there were a few pitches where he kept the knee just off the ground. However, it was always with one leg kicked out, not in the traditional crouch.
MJ Melendez is classified as a traditional catcher. Of his 22 block attempts with a runner on third, he used a traditional setup 20 times and twice used a one-knee setup. A check of 15 blocks he made with a runner on second base found him using the conventional setup all 15 times. The overwhelming preponderance of his blocks came with him in a conventional setup.
There were five catchers who do classify as using setups and being hybrids.
Of Tomas Nido’s eight blocks with a runner on third, five were from a one-knee setup and three were from a traditional crouch. Robinson Chirinos had eight block opportunities with a runner on third. On six of them he used a traditional setup (blocking five of the six and allowing a run to score on the other one) and he successfully blocked two pitches from a one-knee setup.
Of Martin Maldonado’s 13 block chances with a runner on third, he used the one-knee setup five times and the conventional setup eight times.
Tyler Heineman used a one-knee setup on three block attempts and a traditional setup on five block attempts with a runner on third. Reese McGuire used a one-knee setup on two and a conventional setup on three of his five block opportunities with a runner on third base.