Let's get it out of the way first that Salvador Perez, based on the current defensive metrics we have, is a very good defensive catcher. Over the past four seasons and change, Perez has been one of the best defensive catchers in baseball.

2010-2015

Name G Def Yadier Molina 673 88.9 Matt Wieters 587 72.4 Russell Martin 609 67.0 Brian McCann 648 61.7 Carlos Ruiz 582 57.3 Salvador Perez 421 51.0 Jonathan Lucroy 619 47.6 Ryan Hanigan 447 45.5 Buster Posey 615 44.2

You should notice that Perez has been very good in the smallest amount of games listed too. He's been better than Lucroy despite having 200 fewer games and not that far off from Ruiz in 160 fewer games.

Perez is noted for his strong arm and accurate throws that have led him to being one of the best catchers in baseball at managing the run game. Sometimes runners are out before they even break for second/third on the steal.

2010-2015

Name Inn rSB Def Russell Martin 5013.2 22 67.7 Yadier Molina 5618 21 89.8 Salvador Perez 3510 18 51.6 Matt Wieters 4794.2 17 75

Perez ranks 3rd overall in the span on Stolen Base Runs Saved Above Average, as described by Fangraphs as:

rSB: Calculated by The Fielding Bible, Stolen Base Runs Saved measures how many "runs" a catcher contributes to their team by throwing out runners and preventing runners from attempting steals in the first place.

Again the reader should notice it's been accomplished in a meaningful amount of fewer games than others on the list. The same reasoning explains why Perez is far behind the others in the DEF metric. While it's not an exact figure, or one you'd want to take solace in, we can extrapolate Perez's defense given equal innings. This assumes he would continue on his current defensive rate. Note that DEF is an accrual stat, so the compared catchers have done this already and have been rewarded for doing it.

Name DEF Real DEF Perez Difference Martin 67.7 72.6 4.9 Molina 89.8 81.11 -8.69 Perez 51.6 51.6 0 Wieters 75 69.5 -5.5

On a prorated amount, Perez has been better than Russell Martin, but not quite as good as Wieters or near Molina (who he's often compared to).

For clarity, let's look at the other metric of catcher defense (that Perez isn't that good at), Catcher Blocked Pitches (in runs above average).

Overall Name Inn rSB RPP Def 15 Welington Castillo 2394.2 11 4.7 36.3 16 Josh Thole 2712 -8 3.9 19.2 17 Yorvit Torrealba 2511.1 -2 3.7 23.2 18 Salvador Perez 3510 18 3.5 51.6 19 John Buck 4088.2 -8 3.1 30.1 20 Russell Martin 5013.2 22 2.7 67.7

Perez checks at 18th overall in the league from 2010-2015. He's not a superb catcher behind the plate defensively, but he's above average by a few runs. That in tandem with his stolen base runs saved (much like Martin) is what makes him one of the best catcher in baseball, defensively.

Now, there is another factor that hasn't been fully incorporated (if at all) in the grand scheme of defensive catcher value (at least in a WAR sense): pitch framing. Pitch framing isn't necessarily a new concept, but it is in it's relative infancy as far as tracking it or attempting to measure it, then turn it into a run value and ultimately incorporate it into wins above replacement. The foremost source at this point for pitch framing is courtesy of Baseball Prospectus (a great article by them can be found here).

The basic concept of pitch framing is making non-strikes look like strikes. On the whole it doesn't sound like something huge, but over the course of the season the best catchers can squeeze 25+ runs out of extra strikes. For instance in 2011 Jonathan Lucroy added 50 extra runs through pitch framing. Maybe you don't believe that, and maybe that's just too much, but under the current methods of pitch framing it's what has been calculated.

The data that BP presents doesn't let you sort through multiple years (such as 2011-2015) but only single years at a time (or at least I haven't figured out how to do it otherwise). Many many excel V-Lookups later, I've done my best to compile the pitch framing data from 2011 to 2014 (2015 has been a minimal impact on the numbers, for good or bad). The criteria for catchers though is they must have had 400+ pitches caught in 2014. Maybe the minimum in 2014 removed some legacy guys from '11/'12, but I wanted a good collection of guys who stayed at catcher from that time span and eyeballing the list it doesn't look like I'm missing anybody important (Dusty Brown and Jake Fox were cut sadly...)

*Note that 0 doesn't mean they had no chances in that year, but that they were exactly league average

NAME 2014 2013 2012 2011 Total Jonathan Lucroy 16.7 33 27.7 50.2 127.6 Brian McCann 11.8 10.6 27.5 34.2 84.1 Jose Molina 17.5 23.9 29.9 12.4 83.7 Russell Martin 16.4 11.3 20 28.8 76.5 Buster Posey 25.5 20.1 23.8 3.9 73.3 Yadier Molina 3.1 22.5 16.6 16.9 59.1 Chris Stewart 4.9 20.4 11.7 18.9 55.9 Ryan Hanigan 7.2 4.6 18.2 19.2 49.2 Hank Conger 26.3 17.8 0 1.1 45.2

Perez is absent from the list. You actually have to go a ways down to find Perez. He's hanging out in the 72-81 range (out of 89 total)

72. Bryan Holaday -5.2 -1.6 0 -6.8 73. Koyie Hill -1 -3 -0.7 -5.2 -9.9 74. Brett Hayes -2.9 -0.7 -2.8 -4.2 -10.6 75. Anthony Recker -6.5 -3.3 -2.2 -0.5 -12.5 76. Salvador Perez -5.8 1.1 -6.8 -3.1 -14.6 77. Wilin Rosario -1.3 -8.6 -7.3 1.8 -15.4 78. Michael McKenry -3.4 -2.7 -5.7 -3.6 -15.4 79. Gerald Laird -5.3 -3.5 -5.8 -1.9 -16.5 80. A.J. Ellis -6.2 1 -8.7 -2.9 -16.8 81. John Jaso -5.5 -3.2 -3.5 -4.7 -16.9

There he is, 76th overall on my list. For all the other things defensively he does well, pitch framing is not one of them, and truth be told he doesn't really even do it close to average as he falls in the bottom quintile overall. Certainly if Fangraphs were to introduce pitch framing (even under their own calculations) it would likely knock down Sal's overall defensive numbers.

For reference here is that first table with the pitch framing metrics included:

Name G Def PF Yadier Molina 662 89.8 83.7 Matt Wieters 554 75 15.7 Russell Martin 589 67.7 76.5 Brian McCann 590 64.9 84.1 Carlos Ruiz 560 57.3 -25 Salvador Perez 414 51.6 -14.6 Jonathan Lucroy 568 50.6 127.6 Ryan Hanigan 433 45.5 49.2 Buster Posey 476 44.2 73.3

Most of those guys are pretty good at both the defense metrics we currently calculate to create catcher DEF and pitch framing metrics. Maybe with pitch framing Perez would be closer to Ruiz, but also Lucroy would blow past those two and possibly everybody else (he's really, really, really good at framing).

We know what Perez is good, okay, and bad at and we know that Perez isn't a good pitch framer. We could just stop the article there, but I like pictures, so let's add some pictures by the means of what pitches Perez has turned into strikes (through Pitch F/X at least).

Here are the pitches so far this year that Pitch F/X has classified as out of the strike zone (zones 11, 12, 13, and 14) but called third strike (narrowed it to strikeouts for the time being).

It looks like the majority of the pitches above are on fastballs and glove side for Perez. That makes sense as fastball have little to no movement on them (compared to other pitches) and it's probably easier to frame a pitch glove side than reach across the plate.

How about some real life capture of those?

The farthest left red-square

Just to the right of the one above

The red square below the two above (Perez pops up to throw down to 2nd base)

The blue square left and below

Bottom zone red square

That last one is pretty good. Perez probably can't take all the credit as the umpire has to actually call a strike, and maybe in that one he was just ready to go home, but that looks like a ball and Erick Aybar wasn't even thinking about swinging at that.

How about for his career?

I limited it to just terminal events for the plate appearance because it can be hard and cumbersome to find random pitches in random at bats as Pitch F/X doesn't always code what inning the pitch happened in or who was pitching so you have to look at all the at bats by the hitter throughout the game. At least with the terminal results, you know it's at the end of the at bat and was a strikeout.

Here's the farthest left square above:

Sadly it's an off-tilt vantage point, but you can still see Perez receive the ball on what looks like the right-handed chalk of the batters box.

And how about the highest ball turned strike of his career?

Ramon Santiago hunches, but man... that one was at his elbows.

It's unclear if pitch framing is a learned skill or a tool. Many organizations are implementing pitch framing drills with their minor league teams. The Cubs have dedicated practice with all their catchers catching with a pitching machine, focusing on not moving their glove when they receive the ball in the zone or moving into the zone after catching a ball. Maybe Perez can learn to be a better pitch framer as there could be concern for his overall defense if/when pitch framing is incorporated into wins.