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The Odd Case of Salvador Perez And Baseball's Misunderstanding Of Catchers Defense

Written by Skye Paul (@BravesFromLA on Twitter), September 7th 2021


Salvador Perez is clubbing homers at an astounding rate this season. What's to make of him as a player? (2021)


Coming into the 2021 season, Salvador Perez was a widely known name within the baseball community, a consistent top 10 catcher in baseball for the past several years in the eyes of many. Perez, who missed the entirety of the 2019 season due to Tommy John Surgery, had a resurgent (albeit short) 2020 season where he slashed .333/.353/.633 (162 wRC+!) in 37 games. The Royals jumped all over these numbers, agreeing to a four year, 82 million dollar contract (including a 13.5 million dollar club option) with Perez. Impressive numbers without a doubt, drawing lots of attention from the media, wondering if he could replicate that production across a full season.

Well, Perez has done exactly that in the 2021 season. As of September 7th, he's hit an astounding 41 home runs, with a slash line of .277/.317/.548, .865 OPS, fantastic numbers for a catcher.

On the defensive side of things, MLB players, coaches, and executives voted Perez as the third best defensive catcher in the AL (via survey done by Baseball America), and why not? I mean, look at him throw out runners!

Checking out his 2011 prospect summary on, scouts pointed out his "outstanding defensive skills" and noting that he can "really catch and throw." Surely, he's an excellent defender, the scouts and players say so!

Upon reading this information, the average baseball fan would reach the conclusion that Perez is in contention to be the best catcher in baseball. Some already have, check out the comment section under this recent tweet MLB put out:

Honestly, I don't blame them. Baseball media has repeated these narratives time and time again in order to grow the game, and why wouldn't you like Perez or want to question his production? He's a long time veteran who's won a World Series and is having a career resurgence coming off of injury.

But what if I told you that everything I've said so far is misleading, and that most baseball fans are analyzing Salvador Perez in all the wrong ways?


Behind The Scenes - The Offense

There's no denying that Perez is having a great offensive season from a results standpoint. An .865 OPS and 129 wRC+ is excellent for a catcher, considering the league average wRC+ for catchers is 89. Really, Perez is currently 40% more effective at producing runs than the average catcher.

The problem lies in the sustainability and offensive ceiling in these numbers. In short, Perez is producing the maximum amount of offense for his style of play, and is vulnerable to the variability in balls in play.

Perez currently holds a very low 3.9 BB% with an alarming 48.7 O-Swing %. His plate discipline has been among the worst in the league this year. With bad plate discipline, Perez's offensive ceiling is already significantly lower than it could be, as his on-base percentage is essentially guaranteed to be below average.

On the plus side, Perez hits the ball extremely hard. His batted ball numbers are among the top 10% in the league, hitting the ball with average exit velocity of 92.7 MPH. He also is well above average in barrel % and launch angle, meaning he is elevating his hard hit balls. This is why he's been able to hit so many homers.

Averaging just under 13 at bats per home run this season, Perez's power is at the absolute peak. He cannot hit better than he's hitting now with his hitting approach. A ceiling of a 129 wRC+ is great, but when we compare that to other great catchers in the league, that number seems a bit less impressive

Yasmani Grandal (CHW): 160 wRC+

Buster Posey (SFG): 146 wRC+

Will Smith (LAD): 138 wRC+

Mike Zunino (TBR): 125 wRC+

*NOTE: If you don't know/understand wRC+, I suggest you read my article explaining advanced hitting statistics by clicking the button below*

Ok, so maybe Perez isn't the absolute best offensive catcher in baseball, but his defense should carry him to near the top of the list of overall catchers, right?



Behind The Scenes - The Defense

Here's where the huge disconnect between the national media's narrative and the actual statistics occur.

The national media and casual baseball fan claim Perez's defense is elite, citing highlight reels and player opinions. However, the statistics that evaluate catchers defense tell a very different story.

Before we dive into Perez's defensive statistics, it is important that we discuss the skills involved in catchers defense. Many believe throwing out runners to be the main job of a catcher, but that couldn't be further from the truth.

A catcher is the most important defensive position on the field, they are involved in every play of the game. Framing and blocking are the main important skills a catcher should have. While throwing out runners is a flashy play in baseball, it doesn't occur all that much in today's era of baseball, and is largely controlled by factors outside the catcher's control. In essence, base runners steal based on the delivery time of the pitcher, not the pop time of the catcher. If a pitcher takes a long time to deliver the pitch after they start their motion and the runner gets a good jump, there's nothing the catcher can do. The runner is already three quarters down the line and will be safe. Controlling the running game is a small part of the position, yet heavily influences the minds of many fans when discussing catchers defense.

It turns out that the most influential defensive skill a catcher can have is pitch framing. With every pitch of every MLB game tracked, statistics show that consistently "stealing" strikes has the greatest effect on the outcome in the game in terms of runs allowed. Here's a quote from Baseball Prospectus:

"Our data suggest that over the past five years, the teams that have employed good framers like Jonathan Lucroy, Brian McCann, and Jose Molina have received essentially "free" (6+ WAR) MVP-caliber seasons from framing alone."

Part of the reason why this is the case is that there are so many opportunities to frame pitches throughout a game, and while there is an obvious human aspect to calling balls and strikes, better framers will accumulate many more stolen strikes over thousands of attempts.

Baseball Prospectus is the perfect site to use when evaluating catchers because it incorporates both blocking runs and framing runs into their metrics, and Baseball Savant tracks their own version of framing runs. Baseball Reference and Fangraphs don't account for framing as of right now

So, how does Salvador Perez stack up in these metrics?

We'll look at Fielding Runs Above Average (FRAA), Baseball Prospectus's man fielding metric, Catcher Defensive Adjustment (CDA), Baseball Prospectus's catchers defense metric, Blocking Runs (EPAA), Baseball Prospectus's blocking metric, and Baseball Savant's Catcher Framing Leaderboard.


Salvador Perez

FRAA: -9.9 (Worst in MLB)

CDA: -10.1 (Worst in MLB)

EPAA: -1.0

BS Framing Runs: -17 (Worst in MLB)

Perez is, without a doubt, the worst framer in baseball. His -17 framing runs is historically bad, the second lowest catcher is at -8 framing runs. It's the second lowest framing runs ever recorded by Baseball Savant, and not only that, Perez was league worst in the statistic in 2015, 2016, AND 2017 as well. Perez's blocking is also below league average, contrary to what many baseball fans believe.

Almost all of his above average production he has from his bat is negated by his extremely poor defense. Defense is such an important skill for catchers that it can be argued Perez is a below average catcher (@MLBNerds).

But hey, his pop-time is above average at 1.98 seconds!


The conclusion, or lesson, to this article isn't really about Perez. It's about how flawed the average baseball fan analyzes catchers defense. Much of the skill is hard, if not impossible, to judge by the eye test. It's why scouts and players have struggled to analyze the skill, it truly requires data to analyze.

I don't blame Perez for these peripherals, the Royals are infamous for rejecting analytics. They've developed him to have the lowest walk rate and framing runs in baseball, and gave him a massive payday because he's exactly the player they hoped for him to be. And even after the framing metrics get factored in, Perez has earned a respectable 3.2 WARP (Prospectus WAR) this season.

Thanks for reading! Check out some of my other articles at the home page and keep an eye out for new ones coming out soon!

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