I recently made a video about a few AL catchers who dominated the league last season. In it, I noted that Salvador Perez was actually the worst of the 3 catchers featured, even though he had way more PAs, in part because his defense was terrible.
For the casual fan, this might be surprising news. After all, Perez is tied for 6th with the most Gold Gloves by a catcher ever.
The thing about Perez, however, is that he isn't terrible at all aspects of catching defense. Even last year, where he had a -10.3 DEF, he still had an rSB of 5. He was the third-best catcher overall by stolen base prevention. This part of his defense is a major contributor to his 5 Gold Gloves.
So what makes Perez such a dreadful defender? Well, primarily this:
Personally, I sway back and forth on how much I agree with Fangraphs' weighting of pitch framing. Back in 2019, when they updated their WAR calculations to factor in framing, it bumped some players' WAR by more than +/-15 WAR throughout their career (Perez, if you're curious, lost 8.3 fWAR in the update).
But the point stands that as long as fallible human umpires determine the outcomes of pitches, catchers who can steal strikes are immensely valuable.
But what if framing didn't matter at all? This is both a relatively new question and an old reality. Robo-umps have been thrown out as a suggestion to prevent missed ball/strike calls, but it's not certain to happen in the near future. As for framing, it's long been a part of catching, but there wasn't a way to quantify it until recently.
Despite this probably being a far-fetched reality now, let's just see who the best defenders behind plate are when you don't look at framing.
The first thing I wanted to check is how many master framers were not elite steal preventers.
To do this, we're going to look at a stat called rSB. Its only role is to measure a catcher's effectiveness in preventing runners from taking extra bases. This stat moves in ones, which means there are no decimals (unlike framing).
The first thing that stood out to me was how little correlation between framing and rSB there was. Aside from Salvador Perez being a huge outlier, there's really not much to make of the chart.
The next was just how many catchers had rSBs of 0. Of the 81 catchers who played at least 100 innings in the bigs last season, 21 (25.9%) had 0 rSBs.
This includes elite framers like Omar Narvaez, Jacob Stallings, Jose Trevino, and JT Realmuto (who all contributed 8.8 FRM). Max Stassi, who was the league's top framer by Fangraphs' metrics, was worth -1 rSB.
In fact, only one player in the top 15 was worth more than 2 FRM (Tomas Nido had 5 FRM). Conversely, however, only Kyle Higashioka had a FRM of worse than -1 (and Higashioka was worth -2).
Essentially, if framing didn't matter and rSB was the only metric you used to judge a catcher's defense, none of the elite framing catchers would become horrifically bad.
The top catchers by rSB would see a significant boost, however, aside from Nido, the top 5 catchers by rSB were negative framers.
Salvador Perez would see the most value added, as his rSB/FRM gap is easily the largest (a gap of nearly 20).
Ryan Jeffers, who had 5.3 FRM, would see the most value lost, as his -4 rSB was the 2nd-worst in the majors.
In general, however, there was no correlation (inversely or otherwise) between FRM and rSB. Perez was an outlier both in his inability to frame and his skill at throwing out runners, but no other player came even close to matching Perez in any regard.
Another metric we can look at is rGFP. This metric (which stands for runs saved by good fielding plays) operates as our way of assessing blocking ability. It helps us determine who is best at preventing wild pitches and passed balls.
In the olden years, where knuckleballers still existed in ones or twos, this might be a little more difficult to assess. (Doug Mirabelli, famous for catching Tim Wakefield, never had a positive rGFP).
But Steven Wright was the last knuckleballer to accumulate a significant number of innings and hasn't pitched since 2019, so I feel fairly justified in my usage.
Like rSB, rGFP only presents whole numbers. Interestingly, while very slight, there is more correlation between FRM and rGFP than between FRM and rSB. If you squint, you can almost make out an ascending line.
Of course, there is no direct correlation. Omar Narvaez, who's an elite framer, struggled in rGFP, finishing as the 7th worst in the league (which metric?). But of the 10 worst by rGFP, 7 also had negative FRM. Pedro Severino, Zack Collins, and Kurt Suzuki were especially terrible by both metrics.
Additionally, of the bottom 10, only two of these players had positive rSBs.
There were 10 players who finished with 0 rGFP. Of these 10, six of them had FRMs within +/-2. Reese McGuire had the highest FRM of the bunch, with 11.3, while Riley Adams had the worst, at -4.3.
Lastly, a shoutout to the most average catcher. Keibert Ruiz had an rSB and FRM of 0, while his rGFP was 1. He was the only catcher with at least 100 innings to have an FRM of exactly 0.
If framing didn't matter, the list of the best defensive catchers would change completely. Yan Gomes or Yadier Molina were top of the league in both rGFP and rSB, but were both negative framers.
However, the Gold Glove would probably still go to Jacob Stallings in the NL, as he had an rGFP of 9.
What would change for fans' perceptions, then?